Chapter 3: Relief
High in the cold desert of Spiti, in Himachal Pradesh, at heights where no tree grows, villagers have for centuries picked up smooth black stones with a spiral coiled inside them. They are ammonites — the fossilised shells of sea creatures that died on the floor of a warm ocean. Yet here they lie, more than three kilometres above the sea.
The stones are not out of place by accident. They are a record. The rock that now stands as the highest mountains on Earth was once the bed of a sea called the Tethys. When the Indian landmass drifted north and pressed into Asia, that sea floor was crumpled, folded and heaved upward. The Himalayas are the folds; the fossils are the passengers, carried skyward.
This is the first lesson of India’s relief: every mountain, plain and plateau is the outcome of a process, and it still carries the marks of that process for anyone who reads them. The young, sharp Himalayas are still rising. The flat northern plain is a deep trough, filled almost to the brim with the mud those mountains shed. And to the south lies a plateau so old and so worn down that it has quietly watched all of this happen.
Read the land, and it tells you its own history.
Diagram
Fig. 3.0-1 Caption: A schematic profile from the Himalayan crest to the southern coast shows the relief divisions in the order a traveller crossing India would meet them. Brief: Draw a simplified, not-to-scale relief profile running from north (left) to south (right). From left: the edge of the Tibetan/Trans-Himalayan highland, then the sharp high peaks of the Great Himalaya, stepping down through the Lesser Himalaya and the low Shiwalik; then the dead-flat Indus-Ganga-Brahmaputra Plain; then the low, rounded Peninsular Plateau, drawn with a steep abrupt Western Ghats edge and a lower, broken Eastern Ghats edge; then a narrow Coastal Plain; then the sea. Label all five divisions — Himalayan Mountain Complex, Indus-Ganga-Brahmaputra Plain, Peninsular Plateau, Coastal Plain, and the sea. Make the Himalayas clearly the tallest and sharpest, and the plateau distinctly low and worn. Mark ‘North’, ‘South’ and ‘not to scale’.
3.1 The Relief of India: A Land of Contrasts
Relief is the difference in height between the higher and lower parts of a land surface, together with the overall shape those heights give it. A relief map, therefore, is not a picture of what covers the land but of the land itself — its rise and fall, its slopes and levels.
Few large countries pack as much relief into one outline as India does. Within a single day’s flight you can pass over the highest young mountains on Earth, one of the flattest and largest plains anywhere, and one of the world’s oldest worn-down plateaus. Two scatterings of islands, quite different from each other, complete the set.
The study of these surface features is called physiography, and geographers divide India into five broad physiographic divisions: the Himalayan Mountain Complex in the north; the Indus-Ganga-Brahmaputra Plain lying along its foot; the Peninsular Plateau to the south; the Coastal Plains fringing the peninsula; and the Islands in the two seas. This chapter takes them in that order.
We refer to this map through the section that follows.
Map
Map 3.1 Caption: The five relief divisions of India, from the northern mountains to the offshore islands. Brief: Political-plus-relief outline map of India showing the full extent of India as officially defined by the Government of India, including Jammu and Kashmir and Ladakh. Shade and label five divisions distinctly: (1) the Himalayan Mountain Complex as an arc across the north; (2) the Indus-Ganga-Brahmaputra Plain as a broad belt along the mountain foot from the Rajasthan desert to Assam; (3) the Peninsular Plateau as the large triangular block of the south, with the Western Ghats marked as a bold western rim and the Eastern Ghats as a broken eastern rim; (4) the Coastal Plains as thin strips on the east and west; (5) the Islands — the Andaman and Nicobar group in the Bay of Bengal and the Lakshadweep group in the Arabian Sea. Include a simple key. Boundaries as officially recognised by the Government of India.
The Land Is Built And Worn At Once
Every one of these divisions is the outcome of a process, and no landform is permanent. Two kinds of force are always at work on the surface. Internal forces from deep in the earth build the land up, raising mountains and warping the crust. External forces — running water, ice, wind and gravity — wear it down again. The steady wearing-away of the land by weathering and erosion together is called denudation.
The relief we see at any moment is the running balance between building and wearing. Where building has recently won, the land stands high and sharp. Where wearing has had the last word for a very long time, the land lies low and rounded.
India’s three great divisions each tell a different version of that story, as the diagram sets out.
Flowchart
Fig. 3.1-1 Caption: India’s three main relief divisions are each the outcome of a different history — one built up, one filled in, one worn down. Nodes: The land is built up by internal forces and worn down by denudation → three different outcomes. Branch A (mountains): the Indian landmass collides with Asia → old sea-floor rock is folded and pushed up → the Himalayan Mountain Complex — young, high, still rising. Branch B (plain): a deep trough sags south of the rising mountains → Himalayan rivers fill it with alluvium → the Indus-Ganga-Brahmaputra Plain — flat, low, deeply filled. Branch C (plateau): an ancient block of hard rock (the peninsula) → hundreds of millions of years of denudation wear it down → the Peninsular Plateau — low, worn, stable.
How Much Land Is What
A rough estimate made by the Census Commission of India in 1951 gives a useful sense of how India’s surface is shared out among these kinds of relief.
The odd-looking heights are simply metric conversions of round figures in feet — 305 m is about 1,000 ft, 915 m about 3,000 ft, and 2,135 m about 7,000 ft. Read across the table and one fact stands out: nearly half of India is low plain, while true mountain country makes up only about a tenth.
Why Relief Comes First
Relief is placed at the start of the study of India for a reason: it decides so much of what follows. The slope of the land sets the course of every river. The height and line of the mountains decide where the monsoon rain is caught and where it is blocked. The lowlands gather the soil that the highlands lose, and it is on that soil that most people live. Read the relief first, and the climate, the rivers, the soils and the settlements of India begin to make sense.
3.2 The Himalayan Mountain Complex
The Himalayas form a great arc along the northern edge of India, curving for about 2,400 km from the gorge of the Indus in the west to the gorge of the Brahmaputra in the east. Across this arc the mountain belt is nowhere thin: its width ranges from about 160 km to 400 km.
The word ‘complex’ is deliberate. This is not a single ridge but a group of ranges running one behind another, roughly parallel, all along the length of the arc. They rise, on the whole, in steps — lowest on the Indian side, highest toward Tibet.
The Himalayas are young mountains, folded up in geologically recent times, and they have not finished rising. That single fact — a range still being built while it is being worn down — shapes almost everything about their form.
3.2.1 The Three Parallel Ranges
Three ranges make up the main Himalayan belt. From the Indian plains northward they are the Great Himalaya, the Lesser Himalaya and the Outer Himalaya.
The Great Himalaya, or Inner Himalaya, is the highest and innermost range, often called ‘Himadri’. Its crest averages above 6,000 m and it stays snow-covered all year. Almost all the giant peaks are strung along it. Mount Everest, re-measured in 2020 at 8,848.86 m, is the highest point on Earth; Kanchenjunga, on the Sikkim–Nepal border, is the highest peak lying within India’s undisputed territory.
South of the Great Himalaya runs the Lesser or Middle Himalaya, with an average height of roughly 3,700 to 4,500 m and a width of about 80 km. Its important branches are the Pir Panjal and the Dhaoladhar. Between it and the Great Himalaya lie flat-floored longitudinal valleys — the beautiful Kashmir valley and the Kathmandu valley are the outstanding examples. Most of the well-known hill stations, among them Shimla, Mussoorie, Dalhousie, Nainital and Darjeeling, sit on this range.
The southernmost and lowest range is the Outer Himalaya, or Shiwalik, standing only about 900 to 1,200 m high and 10 to 50 km wide. Between the Shiwalik and the Lesser Himalaya lie long flat valleys called duns in the west and duars in the east — level strips ideal for settlement, of which Dehra Dun is the best known.
The cross-section shows how the three ranges rise in steps and why their two faces are so unequal.
Diagram
Fig. 3.2-1 Caption: The Himalayan ranges rise in steps toward the north, each presenting a steep face to the south and a gentle back-slope to the north. Brief: Draw a south-to-north profile (south on the left, north on the right), not to scale. From the left: the flat Indus-Ganga-Brahmaputra Plain, then the low Outer Himalaya (Shiwalik), then a flat-floored dun valley, then the higher Lesser (Middle) Himalaya, then the highest Great (Inner) Himalaya, then the edge of the Tibetan/Trans-Himalayan highland. Draw each range with a distinctly steep southern front and a gentler northern back-slope. Show glaciers accumulating on the gentler northern back-slopes. Label the three ranges, the dun, the plain and the Tibetan side, and mark ‘South’, ‘North’ and ‘not to scale’.
3.2.2 The Offshoots and the Trans-Himalayan Ranges
At each end the neat east–west line of the Himalayas turns sharply, like a hairpin, at the Indus gorge in the west and the Dihang gorge in the east. Beyond these bends run the offshoots of the range.
The north-west offshoots lie beyond the Indus and include the Hazara, the Sulaiman, the Bugti, the Kirthar and the Mekran ranges, most of them outside India. The north-east offshoots lie beyond the Brahmaputra gorge; their Indian portion, running north to south, is the belt of hills called the Purvachal — the Patkai Bum, the Naga hills, the Manipur hills and the Mizo hills — while the Arakan Yoma and Tenasserim ranges lie further off in Myanmar.
North-east of Ladakh rises the Karakoram, a Trans-Himalayan range averaging about 6,000 m. Its highest summit, K2 or Godwin Austen (8,611 m), is the highest peak within India’s territory as officially defined. The Karakoram Pass, at about 5,540 m, has long been a route toward the Tarim basin to the north.
One feature runs through the whole system. Nearly every Himalayan range is steep on its southern side and comparatively gentle on its northern side. Ranges built with this consistent one-way tilt are called orthoclinal. The steepness makes the southern approaches far more formidable, while the gentler northern slopes gather the larger sheets of glacier ice.
3.2.3 Regional Divisions of the Himalayas
Along its 2,400 km length the Himalayan belt is not uniform, and great rivers cut gorges that break it into sections. Following Sir S. Burrard, the range is divided into four regional sections, each named for where most of it lies and each bounded by a river gorge, as the map shows.
Map
Map 3.2 Caption: The four regional divisions of the Himalayas, each set off from the next by the gorge of a great river. Brief: Map of the Himalayan arc showing four sections separated by rivers, over the full extent of India as officially defined (including Jammu and Kashmir and Ladakh). Mark, west to east: Punjab/Kashmir Himalaya (between the Indus and the Satluj), Kumaon Himalaya (between the Satluj and the Kali), Nepal Himalaya (between the Kali and the Tista), and Assam Himalaya (between the Tista and the Dihang). Show and label the bounding rivers — Indus, Satluj, Kali, Tista and Dihang (Tsangpo-Brahmaputra). Boundaries as officially recognised by the Government of India.
The Punjab or Kashmir Himalaya, between the Indus and the Satluj, runs about 560 km, mostly through Jammu and Kashmir and Himachal Pradesh. Its main ranges are the Ladakh, the Pir Panjal, the Dhaoladhar and the Zaskar, and the Zoji La pass here stands at about 3,444 m.
The Kumaon Himalaya, between the Satluj and the Kali, runs about 320 km and is higher than the Punjab section. Great rivers such as the Ganga and the Yamuna rise here.
The Nepal Himalaya, between the Kali and the Tista, is the longest section at about 800 km and the loftiest of all — Everest, Kanchenjunga, Dhaulagiri, Annapurna and Makalu all stand here, and the flat Kathmandu valley lies among them. The Assam Himalaya, between the Tista and the Dihang, extends about 720 km to the eastern hairpin bend.
3.2.4 Western and Eastern Himalayas: A Comparison
Set side by side, the western and eastern ends of the Himalayas behave almost like two different mountain systems. The western Himalayas lie roughly west of 86° E, between the Indus and the Kali; the eastern Himalayas lie east of about 88° E, between the Tista and the Brahmaputra.
They rise in different ways. The western Himalayas climb gradually, in a long series of ranges — the sub-Himalayan hills of Jammu and Kashmir stepping up through Dhaoladhar, Pir Panjal, Zaskar and Ladakh to Kailash and the Karakoram. The eastern Himalayas rise abruptly from the plains of Bihar and West Bengal, with the highest peaks packed close together.
The contrast in rainfall is sharp and it changes the whole landscape. The eastern Himalayas, facing the full force of the Bay of Bengal branch of the monsoon, receive heavy rain — well over 200 cm a year in many parts — and are clothed in dense evergreen forest. The drier western Himalayas, getting under 100 cm in many parts, carry mainly alpine and coniferous forest. The same range, differently watered, wears a different coat at each end.
3.2.5 The Significance of the Himalayas
The Himalayas are far more than scenery. Their sheer height and unbroken length make them the single most influential physical feature of India, and their importance follows directly from their form.
They are, first, a climatic wall. Standing across the north, they intercept the rain-bearing summer monsoon winds and force them to rise and shed their moisture as rain and snow on the southern slopes. In winter they block the cold, dry air of Central Asia from sweeping down over India. Without this wall, much of the country would be far drier and its winters far harsher.
They are, second, the source of rivers. Heavy rainfall, vast snowfields and great glaciers feed the mighty rivers of the north. Because snowmelt keeps them supplied even through the dry season, these rivers flow all year and are called perennial. They, and their hundreds of tributaries, are the basis of life across the whole of north India.
They are, third, the makers of the plain. Descending from the mountains, the rivers carry down enormous quantities of eroded rock and lay it as alluvium — the fine silt, sand and clay a river drops — in the trough at the mountains’ foot. That deposit built the fertile plain of the north, which is why it is often called the gift of the Himalayas.
Beyond this, the well-watered slopes hold great hydroelectric potential; the rise from tropical foothills to alpine heights stacks up a ladder of forests and pastures; and the cool climate, scenery and sacred shrines of the range draw travellers and pilgrims in large numbers. Almost every gift the Himalayas give — rain, rivers, soil, forests, power — can be traced back to their height and their line.
3.3 The Indus-Ganga-Brahmaputra Plain
South of the Himalayas, and running for their whole length, lies the great lowland built by three river systems — the Indus, the Ganga and the Brahmaputra. It is one of the largest stretches of level, fertile land anywhere on Earth, and it is the exact opposite of the mountains that made it.
The plain stretches about 2,400 km from the Satluj in the west to the Ganga delta in the east, all along the foot of the mountains. Its width ranges from about 150 to 300 km — some 280 km near Prayagraj, narrowing to only 90–100 km in Assam. Its surface is famously flat, but that flatness hides real variety of relief.
3.3.1 The Formation of the Great Plain
The plain did not exist ready-made. As the Himalayas rose, a long, deep trough sagged along their southern edge — the foredeep, a downward buckle of the crust in front of a rising mountain belt. Into this trough the Himalayan rivers have poured their load of eroded rock for millions of years.
Load by load, the trough has been filled almost to the brim with alluvium. The result is a plain whose flat surface hides an astonishing depth of river deposit beneath it, resting on a buried floor far below.
3.3.2 The Relief Features of the Plain
Seen from the air the plain looks featureless, yet geographers read across it a set of distinct belts, each the record of how the rivers behaved there. Five features matter most: the bhabar, the tarai, the bhangar, the khadar and the doab.
The bhabar is a narrow belt, 8 to 16 km wide, lying right along the foot of the Shiwaliks. It is built of coarse, pebble-studded, porous beds dumped by streams as they burst out of the hills. The porosity is so high that the streams sink and vanish into it, which leaves the surface dry and poorly suited to farming.
Just south of it lies the tarai, where those same streams rise again to the surface. Because the water re-emerges here, the tarai is a damp, marshy belt of finer alluvium, once thick with forest and wildlife; much of it has since been drained and turned to farmland.
Away from this northern edge, the plain sorts itself into old land and new. The bhangar is the older alluvium, standing as low terraces above the reach of floods; it is often dotted with lime nodules called kankar (concretions of calcium carbonate) and is less fertile. The khadar is the newer alluvium of the flood plain itself, flooded almost every year and given a fresh layer of silt each time, which makes it fertile and intensively farmed.
The last feature is the doab — the strip of land lying between two rivers (the name means, simply, ‘two waters’). Doabs are the natural building-blocks of the western plain, and we meet the most famous of them shortly.
The cross-section shows how these belts follow one another southward from the hills.
Diagram
Fig. 3.3-1 Caption: Across the northern edge of the plain, streams sink into the porous bhabar and rise again in the marshy tarai, before the land settles into old bhangar terraces and new khadar flood plains. Brief: Draw a north-to-south cross-section (north/Shiwalik foot on the left, south on the right), not to scale. From the left: the low Shiwalik edge; then the bhabar as coarse pebble beds with hill streams shown sinking underground (dashed lines diving below the surface); then the tarai as a marshy belt with the streams shown re-emerging at the surface; then a higher bhangar terrace of old alluvium; then a lower khadar flood plain beside a river, with a marked flood level. Label all five belts and show the direction of stream flow (surface, then underground, then re-emerging). Mark ‘North’, ‘South’ and ‘not to scale’.
3.3.3 Regional Divisions of the Plain
Flat though it is, the plain is not one thing from end to end. From the western desert to the eastern hills it falls into four broad divisions, which the map sets out.
Map
Map 3.3 Caption: The four regional divisions of the Great Plain of North India. Brief: Map of the Indus-Ganga-Brahmaputra Plain over the full extent of India as officially defined (including Jammu and Kashmir and Ladakh). Shade and label four divisions: (1) the Rajasthan Plain (the Great Indian or Thar Desert) in the west, between the Aravali Range and the western border; (2) the Punjab-Haryana Plain, showing the rivers that cross it; (3) the Ganga Plain, subdivided and labelled Upper, Middle and Lower; (4) the Brahmaputra (Assam) Plain in the north-east. Show the Aravali Range as the desert’s eastern edge and the main rivers of each division. Boundaries as officially recognised by the Government of India.
The Rajasthan Plain, the Great Indian or Thar Desert, lies between the Aravali Range in the east and the alluvial plain of the Indus in the west. It is a sandy waste broken by ridges and dunes: the dunes average about 8 m near Jaipur and Sikar but rise to 30 m near Barmer, and a few top 100 m. The land slopes gently from about 325 m near the Aravalis to under 150 m near the western border. Rainfall rarely exceeds 25 cm a year. Because so little water leaves the region, much of it has inland drainage — streams that end in inland salt lakes such as the Sambhar rather than reaching the sea — while the seasonal Luni is the one stream of any size.
The Punjab-Haryana Plain was built by the alluvium of five rivers — the Satluj, the Beas, the Ravi, the Chenab and the Jhelum — which is why it is called the land of five rivers. It is made up largely of doabs. From east to west these are the Bist-Jalandhar Doab (between the Beas and the Satluj), the Bari Doab (Beas and Ravi), the Rechna Doab (Ravi and Chenab), the Chaj Doab (Chenab and Jhelum) and the Sind Sagar Doab (between the Jhelum-Chenab and the Indus). Several of these rivers now flow mainly through Pakistan. Along the Shiwalik edge, seasonal torrents called chos have gullied the northern margin, especially in the Hoshiarpur area.
The Ganga Plain, the largest division, lies across Uttar Pradesh, Bihar and West Bengal, with its deltaic end in West Bengal and Bangladesh. It was built by the Ganga and its Himalayan tributaries — the Yamuna, the Gomati, the Ghaghara, the Gandak and the Kosi — with help from peninsular rivers such as the Chambal, the Betwa, the Ken and the Son joining from the south. The plain slopes gently east and south-east and is itself divided into three. The Upper Ganga Plain, in the west, holds the higher Ganga-Yamuna doab, where the alluvium is 1,000 to 2,000 m thick and old bhangar uplands stand clearly apart from the newer khadar lowlands. The Middle Ganga Plain is a transitional belt running about 600 km across eastern Uttar Pradesh and Bihar. The Lower Ganga Plain lies in West Bengal, and the Ganga-Brahmaputra delta makes up about two-thirds of it.
The Brahmaputra Plain, also called the Assam Plain, runs about 640 km from Dhubri to Sadiya and is only 90 to 100 km wide, hemmed in by hills on either side. It was built entirely by the Brahmaputra and its tributaries.
3.3.4 The Significance of the Great Plain
The importance of the plain follows straight from its make-up: deep fertile soil, a flat surface, slow perennial rivers and a workable climate. Put together, these make it one of the most productive and crowded lands on Earth.
The plain is home to roughly half of India’s people, though it makes up less than a quarter of the country’s area — a concentration that its farmland can support. Widespread irrigation has turned parts of it, especially Punjab, Haryana and western Uttar Pradesh, into the granary of India. The flat, open land carries a dense web of roads and railways, and on that base have grown much of the country’s industry, trade and largest cities.
Along the banks of its sacred rivers rose ancient centres of religion and learning, and the plain remains the cultural heart of the country. In relief it may be the plainest division of all, but in the life of India it is the most crowded and the most worked.
3.4 The Peninsular Plateau
South of the Great Plain rises the Peninsular Plateau — the oldest and steadiest part of India. It forms an irregular triangle: its base lies between the Delhi Ridge and the Rajmahal Hills, and its apex is the southern tip of the peninsula. It runs about 1,600 km from north to south and about 1,400 km from east to west, standing generally between 600 and 900 m above the sea.
The plateau is walled by hills on its three sides — the Aravalis, the Vindhyachal and the Rajmahal Hills to the north, the Eastern Ghats to the east, and the Western Ghats to the west. Across the north, the trough of the Narmada and the Tapi divides the whole plateau into three parts: the Malwa Plateau, the Deccan Plateau and the Chhotanagpur Plateau.
Where the Himalayas are young, high and still rising, the plateau is the opposite in every way: ancient, worn low and rigid. It is the surviving core of a very old landmass.
We refer to this map through the rest of the section.
Map
Map 3.4 Caption: The Peninsular Plateau, its three parts, and the hills that wall it in. Brief: Map of India over its full extent as officially defined (including Jammu and Kashmir and Ladakh), with the Peninsular Plateau picked out as a triangular block. Label the three parts — Malwa Plateau (north-west), Deccan Plateau (the main southern block), Chhotanagpur Plateau (north-east). Mark the walling hills: the Aravali Range (north-west), the Vindhya and Satpura ranges (north), the Western Ghats as a bold continuous western rim, and the Eastern Ghats as a broken eastern rim, meeting at the Nilgiri Hills in the south. Mark the Chambal ravines (badland) area. Boundaries as officially recognised by the Government of India.
3.4.1 The Malwa Plateau and the Aravalis
The Malwa Plateau is the north-western part, lying between the Vindhyachal Range and the Aravalis, with the Ganga plain to its north-east. It is a lava plateau — an outlying sheet of the Deccan Trap, the vast beds of basalt lava that cap much of the peninsula — and its weathered basalt gives a fertile black soil.
The plateau slopes gently to the north, so the Chambal and the Betwa flow northward across it to join the Yamuna. Along their courses the Chambal has cut a maze of deep ravines and gullies known as badland — a much-dissected country of bare ridges, useless for cultivation.
Flanking the plateau on the west is the Aravali Range. It is a relict mountain range — the worn-down stump of a once far higher chain, now reduced to broken, discontinuous ridges. It runs about 800 km from near Ahmedabad in Gujarat to Delhi, on a north-east to south-west axis, and reaches its highest point at Guru Shikhar (1,722 m) on Mount Abu. The Aravalis are the oldest mountain range in India.
3.4.2 The Deccan Plateau
The Deccan is the largest of the three parts, a triangular plateau south of the Tapi. The Satpura and Vindhyachal ranges mark its north-western edge; its western and eastern rims are the Western Ghats and the Eastern Ghats. It averages about 600 m, rising to around 1,000 m in the south and sloping to about 500 m in the north.
The key to the Deccan’s drainage is its tilt. The whole plateau slopes gently from its high western edge down toward the east. Because of this, almost all its great rivers — the Godavari, the Krishna, the Kaveri — flow eastward across it to the Bay of Bengal. Only the Narmada and the Tapi run the other way, westward to the Arabian Sea, because they follow rift valleys — troughs where a block of land has dropped between two faults — that already slope west.
Much of the Deccan is built of the Deccan Trap basalt, whose black soil is prized for cotton. The rivers crossing it have cut broad valleys and split it into smaller plateaus — among them the Maharashtra, the Karnataka and the Telangana plateaus.
3.4.3 The Chhotanagpur Plateau
East of the Deccan, the Chhotanagpur Plateau forms the north-eastern projection of the peninsula. It spreads mainly across Jharkhand, with parts in northern Chhattisgarh and the Purulia district of West Bengal, and averages about 700 m in height. It is built mostly of Gondwana rocks, with patches of ancient granite and gneiss and of Deccan lava.
Chhotanagpur is really a staircase of plateaus at different levels. Its highest surfaces, around 1,100 m in the mid-west, are the pat lands — high, flat tops capped with hard laterite. From these heights the land steps down in every direction, and the rivers spread outward like the spokes of a wheel, a pattern called radial drainage. The Damodar, the Subarnrekha and the Koel rivers all rise here; the Damodar itself runs west to east through the middle of the region in a rift valley, and it is along this valley that the Gondwana coalfields — the source of most of India’s coal — are found.
North of the Damodar lies the Hazaribagh plateau, worn almost flat, with the isolated peak of Parasnath (1,366 m) rising in the east. South of the valley is the Ranchi plateau, on which the city of Ranchi sits at about 661 m. The Rajmahal Hills, made of basalt and lava flows, form the plateau’s dissected north-eastern edge.
3.4.4 The Western Ghats
The Western Ghats, also called the Sahyadri, form the plateau’s western rim. They run about 1,600 km from the Tapi in the north to the southern tip of the peninsula, widening from about 50 km in the north to nearly 80 km in the south, and standing on average 900 to 1,100 m high. The western slope drops abruptly, like a giant staircase — a ‘ghat’ in Indian usage — which gives the ranges their name.
The Ghats form an almost unbroken wall, and roads and railways can cross only where gaps break through: the Thal Ghat and the Bhor Ghat in the north, and the wide Palakkad (Palghat) Gap in the south. In their southern part rise the Nilgiri, the Anamalai and the Cardamom Hills, which carry the two highest peaks of the south — Anai Mudi (2,695 m) and Doda Betta (2,637 m).
3.4.5 The Eastern Ghats
The Eastern Ghats skirt the eastern edge of the plateau, running roughly parallel to the east coast from the north-east of Odisha down to the Nilgiris. They are far less of a wall than the Western Ghats. Their average height is only about 600 m, and instead of a single continuous ridge they are a broken, dissected line of hills, about 200 km wide in the north and narrowing to 100 km in the south.
The break is the work of the rivers. The Mahanadi, the Godavari, the Krishna and the Kaveri have all cut clean through the Eastern Ghats on their way to the Bay of Bengal, leaving a range without structural unity and with different local names in different parts — the Nallamalais, the Velikondas and others, with Mahendragiri (about 1,501 m) among the higher points. In the far south the Eastern Ghats swing round to meet the Western Ghats near the Nilgiri Hills.
3.4.6 Western and Eastern Ghats: A Comparison
Placed side by side, the two rims of the Deccan are a study in contrast. The Western Ghats run as a high, continuous wall of 900 to 1,100 m, 50 to 80 km wide, with true structural unity, and they give birth to most of the peninsula’s large rivers. The Eastern Ghats are lower, around 600 m, wider but broken into separate blocks, lacking structural unity, and no large river actually rises in them — the rivers merely pass through.
Their difference shows plainly in a west-to-east profile of the peninsula.
Diagram
Fig. 3.4-1 Caption: Across the peninsula the land rises abruptly at the Western Ghats and tilts gently down to the east, which is why most of its rivers run eastward to the Bay of Bengal. Brief: Draw a west-to-east cross-section (Arabian Sea on the left, Bay of Bengal on the right), not to scale. From the left: the Arabian Sea, a narrow Western Coastal Plain, the steep and high Western Ghats presenting an abrupt western face, then the Deccan Plateau tilting gently downward toward the east, then the lower and broken Eastern Ghats (drawn as separate hills, not a wall), then a wider Eastern Coastal Plain, then the Bay of Bengal. Show the plateau-top rivers flowing east with arrows. Label all features and mark ‘West’, ‘East’ and ‘not to scale’.
3.4.7 The Significance of the Peninsular Plateau
The plateau’s value follows from its ancient, hard-rock make-up. Being the oldest and most stable block in India, it holds the country’s richest store of minerals — iron, manganese, copper, bauxite, chromium, mica and gold — and almost all of India’s coal-bearing Gondwana rocks lie within it.
Its surface soils tell the same story of old rock. The black lava soil (regur) of the north-western plateau is excellent for cotton, while other tracts suit tea, coffee, rubber, millets, spices and oilseeds. The many rivers plunging off the Western Ghats carry great potential for hydroelectric power and irrigation, and the cool heights of the Ghats hold well-known hill resorts. In short, the plateau gives India its minerals, much of its soil wealth and a large share of its water power — all of it inherited from being the country’s oldest land.
3.5 The Coastal Plains
The Peninsular Plateau does not run straight into the sea. On both sides it is fringed by narrow strips of low, level land — the coastal plains — lying between the Ghats and the water. Along the Arabian Sea runs the West Coastal Plain; along the Bay of Bengal runs the East Coastal Plain.
Two relief features give these plains their character, and they are opposites. A delta is the low, fan-shaped tract of alluvium a river builds where it enters the sea and drops its load. A lagoon is a shallow lake of salt or brackish water, cut off from the open sea by a bar of sand or a spit. Where each occurs tells us a great deal about the coast it sits on, as the map shows.
Map
Map 3.5 Caption: The western and eastern coastal plains, with their divisions, deltas and lagoons. Brief: Map of India over its full extent as officially defined (including Jammu and Kashmir and Ladakh), with the coastal plains picked out as narrow strips. On the west, label the three divisions — Konkan (Mumbai to Goa), Kannad (middle), Malabar (south to the tip) — and mark Kochi on its lagoon. On the east, label the Northern Circars (between the Mahanadi and the Krishna) and the Coromandel/Carnatic plain (between the Krishna and the Kaveri), and mark the deltas of the Mahanadi, Godavari, Krishna and Kaveri and the lagoons of Chilika and Pulicat. Boundaries as officially recognised by the Government of India.
3.5.1 The Western Coastal Plain
The West Coastal Plain lies squeezed between the Western Ghats and the Arabian Sea, running from Gujarat to the southern tip. It is a narrow plain, about 64 km wide on average, and it grows narrower as it goes south, because the Ghats crowd close behind it.
It falls into three parts. The northern part, from Mumbai to Goa, is the Konkan, 50 to 80 km wide and marked by estuaries — river mouths that the sea has drowned into wide, funnel-shaped inlets. The middle part is the Kannad plain. The southern part, up to the tip, is the Malabar plain, whose great feature is its lagoons and backwaters — long, calm channels of water behind the shore. It is on one such lagoon that the port of Kochi stands.
3.5.2 The Eastern Coastal Plain
Along the Bay of Bengal stretches the East Coastal Plain, wider and more level than its western twin, running from Odisha to the southern tip. It broadens to 100–200 km in Tamil Nadu but narrows to only about 32 km north of the Godavari.
It has two parts. Between the Mahanadi and the Krishna lies the Northern Circars plain; between the Krishna and the Kaveri lies the Coromandel or Carnatic plain. The great east-flowing rivers — the Mahanadi, the Godavari, the Krishna and the Kaveri — all build wide deltas where they reach the sea. Along this smooth coast, waves throw up a chain of sand bars, and behind them lie India’s best-known lagoons, the Chilika in Odisha and the Pulicat further south.
3.5.3 Western and Eastern Coastal Plains: A Comparison
The two coasts differ in almost every respect, and the differences run back to how each was made. The west coast is a coast of submergence — the land here has sunk, or the sea risen, drowning the river mouths into deep, indented inlets. The east coast is a coast of emergence — a raised, smooth, shallow shore where rivers spread their deltas and bars build across the mouths.
That single difference decides where ships can shelter. The narrow, indented west coast, with deep water close in and drowned mouths for harbours, offers many fine natural ports. The straight, wide east coast, clogged with delta silt and sand bars, offers very few — its harbours mostly have to be built. The sketch sets the two coasts side by side.
Diagram
Fig. 3.5-1 Caption: The west coast is narrow, backed by the Ghats and cut by estuaries; the east coast is wide, with rivers building deltas and lagoons trapped behind sand bars. Brief: Draw two side-by-side sketch profiles. Left panel — a stretch of the western coast: a narrow plain with the Western Ghats close behind, a river entering the sea through a wide drowned estuary, and a sheltered natural harbour in a deep inlet. Right panel — a stretch of the eastern coast: a wide plain, a river building a fan-shaped delta out into the sea, and a lagoon enclosed behind a long sand bar. Label ‘estuary’, ‘natural harbour’ and ‘Western Ghats’ on the left, and ‘delta’, ‘lagoon’ and ‘sand bar’ on the right. Mark ‘West coast’, ‘East coast’ and ‘not to scale’.
3.6 The Islands
India’s land does not end at its shoreline. Two groups of islands, quite unlike each other, carry Indian territory far out into the two seas — the Andaman and Nicobar Islands in the Bay of Bengal to the east, and the Lakshadweep Islands in the Arabian Sea to the west. The difference between the two groups is written into how each was made, as the map and sketch show.
Map
Map 3.6 Caption: India’s two island groups — the Andaman and Nicobar in the Bay of Bengal and the Lakshadweep in the Arabian Sea. Brief: Map of India over its full extent as officially defined (including Jammu and Kashmir and Ladakh), with insets or callouts for the two island groups. Show the Andaman and Nicobar Islands as a long north–south chain in the Bay of Bengal (mark Saddle Peak in North Andaman and Barren Island as an active volcano), and the Lakshadweep Islands as a scatter of small coral islands in the Arabian Sea (mark Minicoy). Give the latitudinal extent of each group. Boundaries as officially recognised by the Government of India.
The Andaman and Nicobar Islands are a long cluster strung out almost in a line, from about 6°45′ N to 13°41′ N. There are as many as 572 islands in the group, with a combined area of about 8,249 sq km. They are the larger and more numerous of India’s islands, and they are hilly: Saddle Peak in North Andaman, at about 730 m, is the highest point. Most of them are built of hard tertiary sandstone and limestone, though some are of volcanic origin — Barren Island is the only active volcano in India. In truth these islands are the exposed peaks of a drowned mountain range, the undersea continuation of the eastern hills that reach down from the Purvachal.
The Lakshadweep Islands could hardly be more different. They are about three dozen small coral reef islands — reefs are the ridges of limestone built up by tiny sea animals called coral polyps in warm, shallow, clear seas. None of them is more than a couple of square kilometres in area, Minicoy being the largest, and they barely rise above the water, standing only a few metres high. Each is ringed by a fringing reef of living coral and encloses a calm, shallow lagoon. They lie between about 8° N and 12°20′ N, just north of the Maldives.
So the two groups differ at every point. The Andaman and Nicobar are eastern, large, numerous, hilly and built of hard sedimentary and volcanic rock; the Lakshadweep are western, tiny, few, flat and built of coral. One is a range of drowned mountains breaking the surface; the other is the slow work of coral, raised barely clear of the sea.
3.7 Summary
The Whole Picture
Relief is the rise and fall of the land. Every landform is a passing balance between forces that build the land up and the denudation that wears it down, and India is divided into five physiographic divisions.
By a 1951 estimate, nearly half of India is low plain and only about a tenth is true mountain — so most Indians live on land that the highlands have shed.
The Himalayan Complex
The Himalayas are young fold mountains, still rising, running about 2,400 km as three parallel ranges — the Great (Himadri), the Lesser and the Outer (Shiwalik) — that step down toward the plains.
Every range is orthoclinal — steep on the south, gentle on the north — which is why glaciers gather on the gentler northern back-slopes.
Beyond the end-bends lie the north-west offshoots and the north-eastern Purvachal hills; the Karakoram carries K2, the highest peak within India’s territory.
River gorges cut the belt into four sections — Punjab/Kashmir, Kumaon, Nepal and Assam — and the wet eastern Himalayas differ sharply from the drier west.
The range earns its importance from its form: it walls off the monsoon and the winter cold, feeds the perennial rivers, and sheds the alluvium that built the northern plain.
The Great Plain
The plain is a deep foredeep trough, filled almost to the brim — nearly 2,000 m of Himalayan alluvium — flat on top and deep beneath.
Its relief belts each record how the rivers behaved: the porous bhabar where streams sink, the marshy tarai where they rise, the old bhangar terraces, the new khadar flood plains, and the doabs between rivers.
It divides into the Rajasthan (Thar) desert, the Punjab-Haryana plain of doabs, the three-fold Ganga plain, and the narrow Brahmaputra plain.
Fertile, flat and watered, it holds about half of India’s people on under a quarter of its area and grows much of the country’s food.
The Peninsular Plateau
The plateau is India’s oldest, most stable block — worn low over ages, rigid and rarely shaken — the exact opposite of the young Himalayas.
The Narmada-Tapi trough splits it into the Malwa Plateau (a lava plateau, with the relict Aravalis and the Chambal badland), the Deccan Plateau, and the Chhotanagpur Plateau (Gondwana coal, radial drainage).
The Deccan tilts from west down to east, so its rivers run east; only the Narmada and the Tapi flow west, along rift valleys.
Its two rims are unequal — the Western Ghats a high continuous wall, the Eastern Ghats low and broken by the rivers that cut across them.
Being old, hard rock, the plateau holds India’s minerals, its coal and its black cotton soil.
The Coastal Plains
Narrow strips fringe the plateau on both sides; their two relief features are deltas, built where rivers drop their load, and lagoons, where water is trapped behind sand bars.
The west coast (Konkan, Kannad, Malabar) is narrow, drowned and indented, with estuaries and fine natural harbours; the east coast (Northern Circars, Coromandel) is wide and smooth, with deltas, lagoons and few harbours.
The Islands
The Andaman and Nicobar Islands in the Bay of Bengal are large, numerous and hilly, built of hard rock and volcano — the peaks of a drowned range, with Barren Island still active.
The Lakshadweep Islands in the Arabian Sea are tiny, few and flat, built of coral and ringed by reefs — the slow work of coral raised just clear of the sea.
The Chapter On One Page
Flowchart
Fig. 3.7-1 Caption: India’s five relief divisions, each read back to the process that made it. Nodes: Forces build the land up and denudation wears it down → five physiographic divisions of India. Branch 1 — Himalayan Mountain Complex: India collides with Asia → sea-floor rock folded and uplifted → young, high, still-rising ranges (Great, Lesser, Outer; orthoclinal). Branch 2 — Indus-Ganga-Brahmaputra Plain: a foredeep trough sags at the mountains’ foot → Himalayan rivers fill it with nearly 2,000 m of alluvium → flat, deep, fertile plain (bhabar, tarai, bhangar, khadar, doabs). Branch 3 — Peninsular Plateau: an ancient hard-rock block → hundreds of millions of years of denudation → old, low, stable plateau tilting east (Malwa, Deccan, Chhotanagpur). Branch 4 — Coastal Plains: rivers deposit and the sea reshapes the edge → deltas and lagoons on the wide east coast; estuaries and natural harbours on the narrow, drowned west coast. Branch 5 — Islands: a drowned mountain range breaks the surface → Andaman and Nicobar (hilly, some volcanic); coral reefs build upward → Lakshadweep (low, coral).
What This Chapter Cannot Tell You
The 1951 area shares, and the other broad national figures, say nothing about the district or the village, where crowding, soil fertility and hazard actually vary. A relief map shows the shape of the land at one moment; it cannot show that the Himalayas are still rising or the plateau still being worn, for that change is far too slow to see. And naming a division tells you its form, not its life — whether its soil is tiring, its coast eroding or its people prospering are questions that relief alone cannot answer.
3.8 Key Terms
alluvium — the fine silt, sand and clay that a river carries and lays down.
badland — a much-gullied, ravine-cut land, bare and useless for cultivation.
bhabar — a narrow, porous belt at the foot of the mountains, where hill streams sink and flow underground.
bhangar — the older alluvium of the plain, standing as low terraces above the reach of floods.
coral reef — a ridge of limestone built up by tiny sea animals called coral polyps in warm, shallow seas.
Deccan Trap — the vast sheets of basalt lava that cap much of the peninsula.
delta — the low, fan-shaped tract of alluvium a river builds where it enters the sea and drops its load.
denudation — the wearing down of the land by weathering and erosion working together.
doab — the strip of land lying between two rivers.
duars — the flat longitudinal valleys of the eastern Himalayan foothills (the eastern counterpart of duns).
dun — a flat-floored longitudinal valley between the Shiwalik and the Lesser Himalaya.
estuary — the wide, funnel-shaped mouth of a river drowned by the tidal sea.
foredeep — the long trough that sags in the crust in front of a rising mountain belt.
inland drainage — drainage that never reaches the sea, ending instead in inland lakes.
khadar — the newer alluvium of the flood plain, refreshed with a layer of silt almost every year.
lagoon — a shallow salt- or brackish-water lake cut off from the open sea by a bar of sand or a spit.
orthoclinal — describing a range that is steep on one side and gently sloping on the other.
perennial — (of a river) flowing all through the year, fed even in the dry season.
physiography — the study of the physical features and relief of the land surface.
radial drainage — a pattern in which rivers flow outward in all directions from a central high, like the spokes of a wheel.
relict — a worn-down remnant of a once far higher mountain range.
relief — the difference in height between the higher and lower parts of a land surface, and the overall shape those heights give it.
rift valley — a valley formed where a block of land has dropped between two faults.
tarai — a damp, marshy belt just south of the bhabar, where the sunken streams rise again to the surface.
3.9 Points to Ponder
The plain that feeds half of India is built entirely from soil the mountains lost. Is the erosion of the Himalayas a loss or a gift — and can it honestly be both at once?
A relief map freezes the land at a single instant, yet the Himalayas are still rising and the plateau is still wearing away. If you could photograph India’s relief once every million years, which division would change the most, and which the least?
The west coast is narrow and rich in natural harbours; the east coast is wide and poor in them. For a country planning its ports and cities, is a ‘difficult’ coast always a disadvantage?
The Aravalis are called a relict range — the worn stump of mountains once perhaps as high as the Himalayas. Does that make them old and finished, or a preview of what the Himalayas themselves will one day become?
Nearly half of India lives on the plain, which is under a quarter of its area. Does this concentration reveal the plain as the country’s greatest strength, or its greatest risk?
The very monsoon that the eastern Himalayas catch as heavy rain, the western Himalayas largely miss. If relief decides who receives the rain, can two ends of the ‘same’ range really be said to share one climate?
3.10 Objective Questions
- The relief belt of the plain where the sunken streams of the bhabar rise again to the surface is the: [1 mark]
- khadar
- tarai
- bhangar
- doab
- The highest peak lying within India’s territory as officially defined is: [1 mark]
- Mount Everest
- Kanchenjunga
- K2 (Godwin Austen)
- Nanda Devi
- Ranges that are steep on the southern side and gently sloping on the northern side are described as: [1 mark]
- relict
- orthoclinal
- residual
- radial
- The two rivers of the Deccan Plateau that flow westward to the Arabian Sea are the: [1 mark]
- Godavari and Krishna
- Narmada and Tapi
- Mahanadi and Kaveri
- Chambal and Betwa
- Assertion (A): The east coast of India has very few natural harbours. Reason (R): Along the straight, emergent east coast, large rivers build deltas and waves throw up sand bars. [1 mark]
- Both A and R are true, and R is the correct explanation of A.
- Both A and R are true, but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
- Assertion (A): The Peninsular Plateau is rarely shaken by strong earthquakes. Reason (R): It is an ancient, rigid, stable block of hard rock. [1 mark]
- Both A and R are true, and R is the correct explanation of A.
- Both A and R are true, but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
- Match each item in Column A with the correct entry in Column B: [1 mark]
| Column A | Column B |
|---|---|
| a. Chilika | i. a gap in the Western Ghats |
| b. Guru Shikhar | ii. an active volcano |
| c. Barren Island | iii. a lagoon |
| d. Palakkad Gap | iv. the highest peak of the Aravalis |
Fill in the blank: The strip of land lying between two rivers in the Punjab plain is called a ______. [1 mark]
State whether the following statement is true or false: The Western Ghats are lower and more broken than the Eastern Ghats. [1 mark]
3.11 Check Your Concepts
Define ‘relief’, and name the five physiographic divisions of India. [2 marks]
What is a lagoon? Give one example from the Indian coast. [2 marks]
State two characteristics of the bhabar belt. [2 marks]
Differentiate between bhangar and khadar. [3 marks]
Give reasons why the tarai is a damp, marshy belt while the bhabar just north of it stays dry. [3 marks]
Distinguish between the Western Ghats and the Eastern Ghats, giving three points of difference. [3 marks]
Explain why most rivers of the Deccan Plateau flow east to the Bay of Bengal, while the Narmada and the Tapi flow west to the Arabian Sea. [4 marks]
Describe the landform character of the Peninsular Plateau, and explain, with evidence, why it is called the oldest and most stable part of India. [4 marks]
Describe the three parallel ranges of the Himalayas, giving the approximate altitude and one distinguishing feature of each. [4 marks]
Describe how the Indus-Ganga-Brahmaputra Plain was formed, and explain why it supports about half of India’s population though it makes up less than a quarter of the country’s area. [6 marks]
“The importance of the Himalayas follows directly from their form.” Discuss this claim with reference to their effect on India’s climate, its rivers, and the building of the northern plain. [6 marks]
3.12 Map, Diagram & Data Interpretation
- Study the cross-section of the Peninsular Plateau (Fig. 3.4-1) and answer: [4 marks]
- Which rim of the plateau is higher and more continuous?
- In which direction does the plateau tilt, and how does this decide the flow of most of its rivers?
- State one thing the single profile line does NOT tell you about the Eastern Ghats.
- The cross-section in Fig. 3.3-1 shows the northern edge of the Great Plain. [4 marks]
- Name the belt where the hill streams sink underground and the belt where they re-emerge.
- Using the diagram, explain why the bhabar is dry and the tarai marshy.
- Using the figures in Table 3.1: [3 marks]
- What percentage of India’s land area is classed as plateau?
- Add the mountainous and hilly shares — what percentage of India is broadly upland?
- State one thing this 1951 estimate does NOT tell you.
- On an outline map of India, mark and label each of the following: [6 marks]
- the Shiwalik Range
- the Aravali Range
- the Western Ghats
- the Karakoram Pass
- the Chilika lagoon
- the Deccan Plateau
- Using the heights in Table 3.2: [3 marks]
- Calculate how much higher Mount Everest stands than Nanda Devi.
- Name the listed peak that lies within India’s undisputed territory.