Maarg Manthan · Topic 8.2

Geological Regions of India: Deccan Plateau, The Himalayas, Other Peninsular Mountain Ranges, Indo-Gangetic-Brahmaputra Plain

Geography › Physical Geography of India · Topic 8.2

India has three great geological regions. The Peninsular block is the oldest and most stable, made of ancient crystalline rocks, with the Deccan Plateau, the Central Highlands and hill ranges such as the Aravalli, Vindhya, Satpura, Western Ghats and Eastern Ghats. The Himalayas in the north are the youngest and highest fold mountains, still rising. Between them lies the Indo-Gangetic-Brahmaputra plain, a vast alluvial lowland formed by the deposits of rivers. India's physical divisions are grouped as the Himalayan mountains, the Northern Plains, the Peninsular Plateau, the Indian Desert, the Coastal Plains and the Islands.

14 min read · UPSC Prelims · Geography · Physical Geography of India

At a Glance

Oldest region Peninsular block
Youngest region Himalayas
Plain Indo-Gangetic-Brahmaputra alluvial plain
Plateau Deccan and minor plateaus
Hill ranges Aravalli, Vindhya, Satpura, Western and Eastern Ghats
Exam link UPSC Prelims, Geography: Physical Geography of India

Where Does It Fit?

This topic follows the location of India and describes the land itself: its three geological regions and their landforms. The rivers, climate and soils of India described later are all products of this relief. Previous topic: Geographical Location of India and Its Geopolitical Importance. Next topic: Drainage System of the Himalayan Rivers: Indus, Ganga, Brahmaputra River Networks.

What Are the Five Physical Divisions?

In short: India has a young mountain wall in the north, a river-built plain below it, an ancient plateau, fringing coasts and two island groups.

Division	Origin and age	Main features	Stability
The Himalayas	Young fold mountains from the collision of the Indian and Eurasian plates, as in Plate Boundaries: Divergent, Convergent, Transform	Three parallel ranges, the Greater Himalaya, Lesser Himalaya and Shiwaliks, with the trans-Himalaya and the Purvanchal in the east	Youngest and the most unstable; earthquakes and landslides
The Indo-Gangetic-Brahmaputra Plain	Alluvium laid down by the Indus, Ganga and Brahmaputra systems in a foredeep at the foot of the Himalayas	Flat, featureless and fertile; the Punjab, Ganga and Brahmaputra plains and the delta	Young and sensitive to earthquakes along the Himalayan front
The Peninsular Plateau	One of the oldest and most stable land masses, a part of ancient Gondwanaland	Rolling plateau with hill ranges, the Deccan Trap in the west, and mineral wealth	Stable; earthquakes are rare and mild
The Coastal Plains	Built by sediments from rivers and by uplift or submergence of the coast	Narrow western coastal plain and broad eastern coastal plain with deltas	Stable
The Islands	Lakshadweep are coral atolls, and the Andaman and Nicobar Islands are a tectonic island arc, an extension of the Arakan Yoma	Coral reefs in Lakshadweep; hills, forests and Barren Island, the only active volcano in India, in the Andaman and Nicobar group	Lakshadweep is stable but vulnerable to sea-level rise, while the Andaman and Nicobar Islands are seismically active

The Lakshadweep is considered part of the volcanic chain of the Reunion hotspot, built up by coral over the sunken peaks, as in Minor Relief Features: Mid-Oceanic Ridges, Seamounts, Submarine Canyons, Guyots, Atolls. The Andaman and Nicobar Islands lie on the subduction zone of the Indian and Burmese plates, which gave rise to the 2004 earthquake and tsunami, as in Plate Boundaries: Divergent, Convergent, Transform.

How Are the Himalayan Ranges Arranged?

In short: the Himalayas rise in three steps from the plains, from the low Shiwaliks to the Lesser Himalaya to the great snow-covered Himadri, with the Trans-Himalaya behind them.

Range	Height and size	Features
Shiwaliks (Outer Himalaya)	600 to 1,500 m; about 2,400 km from the Potwar plateau to the Brahmaputra valley; width from 50 km in Himachal Pradesh to under 15 km in Arunachal Pradesh	The youngest range, 2 to 20 million years old; made of unconsolidated sand, gravel and conglomerate carried by rivers and folded by the northward push of the plate; southern slopes steep, northern slopes gentle; heavily cut by seasonal streams called chos; forested in the east, almost bare in the west; duns lie between them and the Lesser Himalaya
Lesser Himalaya (Himachal, Middle Himalaya)	3,500 to 4,500 m, with peaks above 5,000 m; 60 to 80 km wide	Metamorphic rocks and granites; steep bare southern slopes and gentler forested northern slopes; Pir Panjal, Dhauladhar, Mussoorie and Nag Tibba, Mahabharat Lekh in Nepal; hill stations such as Shimla, Mussoorie, Nainital and Darjeeling
Greater Himalaya (Himadri)	Average height about 6,100 m, width about 25 km	Granite and gneiss core with metamorphosed sediments; snow-covered all year; highest peaks; asymmetric folds with steep south slope and gentle north slope, a hogback; source of the great glaciers; passes above 4,500 m
Trans-Himalaya (Tibetan Himalaya)	Average about 3,000 m; about 1,000 km east-west; 40 km wide at the ends and 225 km in the middle	Zanskar, Ladakh, Kailas and Karakoram ranges; dry, cold, high-altitude desert; Indus rises north of the Kailas range
Purvanchal (Eastern Hills)	Mostly 1,500 to 3,800 m	The Himalaya turns south at the Dihang gorge; Patkai Bum, Naga Hills, Manipur Hills and Mizo Hills; the watershed between India and Myanmar

The ranges are separated by major thrust faults: the Main Frontal Thrust between the Shiwaliks and the plains, the Main Boundary Thrust between the Shiwaliks and the Lesser Himalaya, and the Main Central Thrust between the Lesser and Greater Himalaya. They are the surfaces along which the plates are still moving, which is the reason for the seismic hazard, as in epicentre above it Main cause Sudden slip along faults at plate boundaries Scales Magnitude…">Earthquakes: Types, Causes, Effects and Frequency.

How Was the Great Plain Formed?

In short: the Himalayas rose, the rivers cut them down, and the sediment filled the trough in front of them to make an alluvial plain.

When the Indian plate collided with Eurasia, the Tethys sea between them was squeezed, and a long depression, the Indo-Gangetic trough or foredeep, formed in front of the rising Himalayas, as in Plate Boundaries: Divergent, Convergent, Transform. Rivers coming from the young mountains carried huge amounts of gravel, sand and silt into the trough, and the glaciers and new rivers added more. Over millions of years, the Tethys receded and the trough was filled to form a monotonous, featureless plain. Peninsular rivers, such as the Chambal, Betwa, Ken and Son, added a small share. Today the plain is built mainly by the Indus, the Ganga and the Brahmaputra with their tributaries, and so it is named after them. The alluvium is thick: the depth to the basement rocks reaches about 6,000 m in places, though it varies greatly.

What Are the Features of the Plain?

Size and form: an arcuate plain about 3,200 km from the Indus mouth to the Ganga mouth, about 2,400 km within India, up to about 500 km wide in the west, narrowing in the east. The Shiwaliks mark the north, an irregular line along the Peninsula marks the south, and the Purvanchal the east.
Flatness: the average elevation is about 200 m, with the highest point of about 291 m near Ambala, which forms the divide between the Indus and Ganga systems. The gradient is about 20 cm per km from Saharanpur to Kolkata and falls to about 15 cm per km from Varanasi to the delta, so rivers flow slowly, meander and shift their courses.
Depositional landforms: levees, bluffs, oxbow lakes, marshes, ravines and braided channels, as in Running Water Depositional Landforms: Alluvial Fans, Deltas, Floodplains, Natural Levees, Meanders, Oxbow Lakes, Braided Channels.

Belt	Position and nature	Features
Bhabar	Northernmost, 8 to 16 km wide, at the foot of the Shiwaliks	Coarse pebbles and boulders in alluvial fans; very porous so that streams disappear underground; unsuitable for farming; large trees only
Terai	South of the bhabar, 15 to 30 km wide	Streams re-emerge here; damp, marshy, forested, with wildlife in Corbett and Kaziranga; broader in the east, where rain is higher; much of it has been cleared for sugarcane, rice and wheat
Bhangar	Older alluvium on higher terraces away from the rivers	Clayey, dark, with lime nodules called kankar; fossils of rhinoceros and elephants; regional forms are the Barind plains of Bengal and the bhur of the upper Doab
Khadar	Newer alluvium on flood plains	Renewed by floods almost every year; sandy loams; the most fertile soils of the Ganga
Reh or Kallar	Saline patches in drier areas such as Haryana	Salts brought to the surface by capillary action under irrigation; spreading with canal irrigation

What Is the Peninsular Plateau?

In short: the Peninsular Plateau is India’s oldest, most stable landmass, a patchwork of smaller plateaus separated by hills and river valleys.

The Peninsular Plateau is a tableland made mostly of ancient crystalline rocks, and a part of the old Gondwanaland. It has not been submerged under the sea for hundreds of millions of years except in a few places. It covers about 16 lakh sq km, with an average height of 600 to 900 m, and slopes from west to east, as shown by the flow of most of its rivers to the Bay of Bengal. The Narmada and Tapti are exceptions that flow west in rift valleys. The Western Ghats form its steep western edge and the Eastern Ghats its broken eastern edge. Weathering and erosion over a long time have reduced it to a rolling surface with residual hills.

What Are the Meghalaya and Deccan Plateaus?

Meghalaya (Shillong) Plateau: the Meghalaya Plateau is an eastward extension of the Peninsula, cut off from the main block by the Garo-Rajmahal gap, a fault depression later filled by Ganga and Brahmaputra sediments. It has the Garo, Khasi-Jaintia and Mikir hills, with Shillong at 1,961 m as the highest point, and the heaviest rainfall in India at Mawsynram and Cherrapunji, as in Types of Precipitation: Convectional, Orographic, Cyclonic, Frontal, Monsoonal.
Deccan Plateau: a triangular plateau of about five lakh sq km, bounded by the Satpura and Vindhya in the north-west, the Mahadev and Maikal in the north, and the Western and Eastern Ghats. It has an average height of about 600 m, rising to 1,000 m in the south, and slopes eastward.
Maharashtra Plateau: the northern part of the Deccan, mostly Deccan Trap basalt with step-like flat-topped hills, and regur black soil in the wide valleys of the Godavari, Bhima and Krishna.
Karnataka (Mysore) Plateau: 600 to 900 m, divided into the hilly, forested Malnad in the west and the rolling Maidan of low granite hills in the east. The Baba Budan Hills have Mullayanagiri, about 1,930 m, the highest peak in Karnataka.
Telangana Plateau: 500 to 600 m, drained by the Godavari, Krishna and Penneru, of gneiss with peneplains.
Chhattisgarh Plain: the saucer-shaped basin of the upper Mahanadi, between 250 and 330 m, and the only plain worth the name on the plateau, known as the rice bowl of central India.

The Peninsula is the mineral storehouse of India: iron ore, manganese, bauxite, mica, copper, gold, chromite and almost all of the Gondwana coal. The black soil of the north-west suits cotton, the hill regions grow tea, coffee and rubber, and the rivers of the Western Ghats provide hydropower. As an analytical point, the plateau is stable but not uniform: the same ancient block carries mineral-rich tribal uplands in Chotanagpur, the most fertile black soil in Maharashtra and the high rainfall of Meghalaya, so development questions of mining, forests and displacement are concentrated here, as in Ferrous Metallic Minerals: Iron Ore, Manganese, Chromium, Nickel, Tungsten.

What Are the Northern Ranges: Aravalli, Vindhyan and Satpura?

Range	Extent	Features
Aravalli	About 800 km, from Delhi to Palanpur in Gujarat, trending north-east to south-west	One of the oldest fold mountains in the world and the oldest in India; once much higher, now worn to residual ridges of 400 to 600 m; continuous south of Ajmer; Guru Shikhar (1,722 m) on Mount Abu is the highest peak; passes at Pipli Ghat, Dewair and Desuri; a barrier to the advance of the Thar desert and a source of water recharge
Vindhyan Range	Over 1,200 km, from Jobat in Gujarat to Sasaram in Bihar, north of the Narmada-Son trough	Horizontally bedded ancient sedimentary rocks; 300 to 650 m; continues east as the Kaimur and Barner hills; a watershed between the Ganga system and the rivers of the south
Satpura Range	About 900 km, between the Narmada and the Tapti, east-west	Seven mountains; parts are a horst, a block uplifted by faulting; Dhupgarh (1,350 m) near Pachmarhi is the highest; Amarkantak (1,127 m) is the source of the Narmada and Son; the Mahadeo and Maikal hills belong to it

The Narmada and the Tapti flow west in rift valleys between these ranges. The Narmada-Son trough also marks the traditional divide between north and south India. The Aravalli range is now in the news. In November 2025 the Supreme Court accepted a definition under which only landforms 100 m or more above local relief count as Aravalli hills; critics feared it would open much of the range to mining, and on 29 December 2025 the Court put that order in abeyance and ordered a new expert committee, which has been given time until 30 November 2026 to report, so the legal definition remains unsettled. The Aravalli is also the focus of the Aravalli Green Wall, a plan for a belt of green cover to check desertification.

What Are the Western Ghats?

Extent: from the Tapti valley at about 21 degrees north to near Kanyakumari at about 11 degrees north, about 1,600 km, the western edge of the Deccan. They are not true mountains but the faulted edge of the plateau, and rise steeply like a wall to an average of about 1,000 m from the narrow coastal plain, while sloping gently east.
Northern section: made of horizontal Deccan lava, giving a stair-like or trap topography, averaging about 1,200 m. Kalsubai (1,646 m) near Igatpuri is the highest in Maharashtra. Thal Ghat and Bhor Ghat carry road and rail from Mumbai to the plateau.
Middle Sahyadri: from about 16 degrees north to the Nilgiris, dense forests, with Vavul Mala (2,339 m) and Kudremukh (1,892 m). The Nilgiris rise above 2,000 m at the junction of Karnataka, Keralam (Kerala) and Tamil Nadu; Doda Betta (2,637 m) is the highest, and they meet the Eastern Ghats.
Southern section: separated by the Palghat (Palakkad) Gap, a low rift valley about 30 km wide that carries roads and railways between Keralam and Tamil Nadu and lets the southwest monsoon penetrate inland. South of it rises Anai Mudi (2,695 m), the highest peak of peninsular India, from which the Anaimalai, Palani and Cardamom hills radiate.

The Western Ghats are a UNESCO World Heritage Site since 2012 and a global biodiversity hotspot. They are the source of the Godavari, Krishna and Kaveri, and they cause the heavy orographic rainfall of the west coast, as in Types of Precipitation: Convectional, Orographic, Cyclonic, Frontal, Monsoonal. Landslides in Wayanad in July 2024 killed hundreds of people and reignited the debate over conservation. The Gadgil committee of 2011 and the Kasturirangan committee of 2013 recommended zoning, and the Ministry of Environment re-issued its seventh draft notification of about 56,826 sq km of ecologically sensitive area in July 2026; it is still a draft, with Karnataka opposing it.

What Are the Eastern Ghats, and How Do They Differ?

The Eastern Ghats run parallel to the east coast from the Mahanadi in Odisha to the Vagai in Tamil Nadu, but they are a series of broken, detached hills, cut through by the Mahanadi, Godavari, Krishna and Kaveri. Only between the Mahanadi and the Godavari do they show true mountain character, with the Maliya and Madugula Konda ranges and Mahendragiri (1,501 m); the Araku valley is here. Between the Godavari and Krishna they are low and covered by Gondwana formations of the Krishna-Godavari basin. They reappear as the Nallamalai range in Andhra Pradesh, and farther south as the Javadi, Shevaroy and Biligiri Rangan hills, before merging with the Western Ghats in the Nilgiris.

Feature	Western Ghats	Eastern Ghats
Continuity	Continuous, with only the Palghat Gap	Discontinuous, cut by large rivers
Height	Higher; Anai Mudi 2,695 m	Lower; Mahendragiri 1,501 m
Relation to coast	Close to the coast, with a narrow plain	Farther from the coast, with a broad plain
Rainfall	Very heavy on the windward slope	Moderate; in the rain shadow in the southwest monsoon
Rivers	Short west-flowing streams and the source of the east-flowing rivers	Rivers cross through gaps to the sea

As an analytical point, the ranges explain much of the Indian map: the Aravalli shapes the climate boundary of Rajasthan, the Vindhya-Satpura belt divides the river systems, and the Ghats decide the monsoon rainfall. All of them are old and worn, and the real risk is human: mining, quarrying, plantations and construction on steep slopes make them prone to landslides.

Why Is This Topic Important?

Foundation Frame for all Indian geography
Facts Relief shares asked
Link Geology and hazards

What Came Next?

The next topic describes the drainage system of the Himalayan rivers: the Indus, Ganga and Brahmaputra networks. Next topic: Drainage System of the Himalayan Rivers: Indus, Ganga, Brahmaputra River Networks.

Key People and Terms

Physiography Study of landforms
Gondwanaland Ancient southern supercontinent
Foredeep Trough in front of a mountain range
Barren Island India’s active volcano
Atoll Ring of coral
Arakan Yoma Myanmar range continuing to the Andaman Islands

Exam Corner

Points to Remember

Five divisions: Himalayas, Plains, Plateau, Coasts, Islands.
Plains are about 43 per cent of the area.
Peninsula is the oldest and most stable block.
Barren Island is the only active volcano.
Lakshadweep consists of coral islands.

Do Not Confuse With

Lakshadweep and Andaman and Nicobar Coral atolls versus tectonic island arc
Hills and mountains 305 to 2,135 m versus above 2,135 m
Plateau and plain Elevated ancient block versus low alluvial lowland

Memory Hook

Young mountains, fertile plains, old plateau, fringing coasts, two island worlds.

Mains Angle

Questions ask for contrasts between the divisions. These points add depth.

Age Young versus ancient
Stability Earthquake-prone versus stable
Economy Water, food, minerals, ports

A Question You May Face

An original practice question, not a past paper question.

“Describe the major physical divisions of India and bring out the contrast between the Himalayas and the Peninsular Plateau.”

How to Answer

Divisions Five.
Contrast Age and stability.
Share Plains, plateau, hills.
Role Water, food, minerals.

GS Relevance

Prelims: physical divisions, features of the Himalayan ranges, plateau, hills and plains of India. GS Paper 1: physical geography of India.

Frequently Asked Questions

What are the major physical divisions of India?

India has five major physical divisions: the Himalayan mountains, the Indo-Gangetic-Brahmaputra plain, the Peninsular Plateau, the coastal plains, and the islands, which include Lakshadweep and the Andaman and Nicobar Islands. They differ in age, rocks, relief and geological stability.

Which is the youngest and most unstable physical division of India?

The Himalayas are the youngest and most unstable division, formed by the collision of the Indian plate with the Eurasian plate. Tectonic movement is still active, causing frequent earthquakes and landslides, and the mountains are still rising slowly.

Which is the oldest and most stable division of India?

The Peninsular Plateau is the oldest and most stable land mass of India. It was part of the ancient Gondwanaland and is made of very old crystalline rocks, with little earthquake activity, and it holds most of India's mineral resources.

Which is the oldest mountain range of India?

The Aravalli Range, about 800 kilometres long from Delhi to Gujarat, is the oldest fold mountain range in India and one of the oldest in the world. It was once much higher, but long erosion has worn it down to residual hills, with Guru Shikhar on Mount Abu at 1,722 metres as the highest peak.

What is the Palghat Gap?

The Palghat or Palakkad Gap is a low pass, about 30 kilometres wide, in the Western Ghats between the Nilgiris and the Anaimalai hills. It connects Keralam with Tamil Nadu by road and rail, and allows the southwest monsoon winds to blow inland to bring rain to the Coimbatore region.

PYQ Practice — Statement Analysis

1 The Peninsular Plateau is one of the most stable land masses of the world.

True

It is formed of very old rocks.

2 Barren Island is located in the Lakshadweep.

False

It is in the Andaman and Nicobar Islands.

3 The Aravalli Range is the oldest fold mountain range in India.