Big picture
India's physical landscape includes young folded mountains, broad alluvial plains, an ancient plateau, desert, coasts and islands. These are not arbitrary map divisions: they reflect geological history and continuing erosion, transport and deposition. Their differences influence rivers, soils, settlements and transport routes.
A journey from the northern plains towards the Himalayas crosses changing slopes, sediments and rock structures. A journey southwards towards the peninsula encounters another geological setting. This chapter explains the main structural divisions and then develops the physiographic regions needed for comparison and map-work.
Learning goals
Distinguish structural divisions from present physiographic regions.
Explain Himalayan origin and its longitudinal and regional divisions.
Describe the formation and subdivisions of the northern plains.
Compare peninsular plateau regions and the two Ghats.
Explain desert, coastal and island characteristics.
Interpret physiography through river, settlement and hazard examples.
Core ideas
1. Geological framework
The peninsular block is an old, comparatively stable part of the Indian landmass, though faults, uplift and volcanism have affected it. The Himalayas and northeastern hills form a geologically younger zone strongly shaped by convergence. The Indo-Ganga-Brahmaputra plain is a sediment-filled lowland adjoining the mountain system.
Structural divisions concern underlying geological development; physiographic divisions describe broad surface relief. For example, an alluvial plain can overlie a deep sedimentary basin, while exposed crystalline rocks form much plateau relief. Calling the peninsula stable does not mean completely free from earthquakes or landscape change. Stability is relative to the active mountain belt and geological time scale.
2. Himalayan origin and longitudinal belts
Indian–Eurasian convergence compressed, folded and uplifted material associated with the intervening Tethys and continental margins. Continued movement contributes to earthquakes and active relief development. The Himalayas are not the eroded remains of an unchanged ancient plateau.
Belt | Position and character | Important example or feature |
|---|---|---|
Greater Himalaya or Himadri | Northernmost principal continuous high belt | High peaks and extensive snow and ice |
Lesser Himalaya or Himachal | South of Himadri | Pir Panjal and Dhauladhar ranges |
Shiwalik | Outer lower belt | Relatively young sedimentary hills |
Duns are longitudinal valleys associated with the outer Himalayan setting; Dehra Dun is an example. The belts differ in height, structure and material, so a single description cannot represent the entire mountain system.
3. Regional Himalayan diversity
The Kashmir or northwestern Himalaya includes ranges, high valleys and intermontane basins. The Kashmir Valley contains lake-related and alluvial deposits; karewas are terrace-like deposits important in regional farming, including saffron cultivation in suitable areas. High passes and relief strongly influence routes.
The Himachal and Uttarakhand Himalaya contain major ranges and headwaters of Himalayan rivers. The Darjeeling and Sikkim Himalaya combine steep relief, high rainfall in many sectors and important ecological variation. The Arunachal Himalaya is deeply dissected by rivers, while eastern hills extend southwards in ranges including Patkai, Naga, Manipur and Mizo hills. Locate major sectors and rivers rather than assuming every Himalayan valley has identical climate or land use.
4. Formation of the northern plains
The northern plains developed through deposition by the Indus, Ganga, Brahmaputra and their tributaries in the foreland lowland. Repeated river movement and sediment accumulation produced extensive flat surfaces, but the plain contains distinct belts and active channels.
Bhabar is a coarse, porous belt near the Himalayan foothills where streams may disappear into sediments. The Terai, farther south, has a higher water table and re-emerging streams, producing wetter conditions. These belts are not interchangeable: particle size and drainage explain their contrasting character.
Bhangar refers to older alluvium commonly forming relatively higher surfaces; khadar is newer alluvium associated with active floodplains. For example, a khadar area can have fertile renewed deposits while remaining exposed to floods and channel change. Fertility does not mean absence of hazard.
5. Peninsular plateau framework
The peninsular plateau consists of uplands, residual hills and valleys developed largely on old rocks, with extensive lava-covered areas in the Deccan. Faulting and river erosion create local contrasts. The Narmada and Tapi occupy important westward-draining trough-like settings associated with structural controls.
The Central Highlands lie broadly north of the Narmada, including the Malwa region and related uplands. The Deccan Plateau extends broadly southwards, with a general eastward drainage tendency over much of its area. The Chota Nagpur Plateau is important for mineral resources, while the northeastern plateau includes the Meghalaya upland, separated from the main peninsular exposure by intervening lowland. Geological continuity does not require a continuous exposed surface today.
6. Western and Eastern Ghats
Feature | Western Ghats | Eastern Ghats |
|---|---|---|
Position | Western edge of peninsular plateau | Eastern plateau margin |
Continuity | More continuous overall | More broken by major east-flowing rivers |
General elevation | Higher on average | Lower on average |
Climatic role | Strong barrier to southwest-monsoon winds | More discontinuous barrier |
Major river relationship | Many rivers originate near them | Major peninsular rivers cut through them |
The Nilgiri region connects southern uplands, while Anaimalai and Cardamom hills lie farther south. Anamudi is the highest peak of peninsular India. For example, the Western Ghats' steep western face and rainfall contrast with interior areas influence settlement and agriculture. Do not transfer this contrast mechanically to every season or every small valley.
7. Indian desert
The Thar Desert occupies much of western Rajasthan and adjoining areas. Aridity reflects low rainfall and high moisture demand, with wind-shaped dunes, sparse vegetation and episodic drainage. Barchans and other dune forms occur, but water also shapes channels and deposits during occasional storms.
The Luni is an important river of the arid western region. Many streams are seasonal and may lose water through infiltration and evaporation before reaching an open sea. For example, an interior drainage basin can accumulate salts where water evaporates. Desert does not mean no settlements or farming: irrigation and pastoral adaptations can support livelihoods while creating resource-management challenges.
8. Western coastal plains
The western coastal plain lies between the Arabian Sea and Western Ghats and is generally narrower than the eastern coastal plain. It includes the Konkan, Kannad or Karnataka coastal sector, and Malabar in the commonly used broad divisions.
Short steep rivers, estuaries, ports and lagoons characterise different sectors. Kerala's backwaters, including the Vembanad system, are important for transport, fishing and local livelihoods. Their origin and maintenance involve coastal barriers, sediment and water exchange. For example, a lagoon behind a coastal barrier differs from a delta distributary even though both contain water near the sea. Avoid calling the entire coast uniformly rocky or uniformly sandy.
9. Eastern coastal plains
The eastern coastal plain lies between the Bay of Bengal and Eastern Ghats and is generally broader. Northern and southern divisions include the Northern Circars and Coromandel Coast. Large east-flowing rivers such as the Mahanadi, Godavari, Krishna and Kaveri form important deltaic areas.
Chilika is a major lagoon in Odisha; Pulicat is another important lagoon farther south. The eastern coast is exposed to Bay of Bengal cyclones and storm surges, while fertile deltas support dense settlement and farming. A source question can therefore link depositional opportunity with hazard exposure. Broad coastal width alone does not determine vulnerability: elevation, shelters, ecosystems and preparedness also matter.
10. Islands and map interpretation
The Andaman and Nicobar Islands form an elongated group in the Bay of Bengal associated with a tectonically active region. Barren Island is volcanic. The Ten Degree Channel separates the Andaman and Nicobar groups, and Great Nicobar contains Indira Point.
Lakshadweep consists mainly of coral islands in the Arabian Sea. Reef growth requires suitable marine conditions and is sensitive to environmental change. Island physiography therefore differs from both peninsular plateau rocks and river-built northern plains. On an outline map, label the Himalayas, northern plains, Aravalli, Western and Eastern Ghats, Deccan, Thar, major deltas and both island groups. Explain the process behind each region when the question asks for more than location.
A reliable approach to questions
Identify whether the question asks for geological origin, relief characteristics or location.
Organise comparisons by age, material, height, drainage and process.
Explain depositional plains separately from tectonic mountains and old plateau regions.
Add specific examples and label map items accurately.
Link physical features to livelihoods or hazards without claiming a single feature determines everything.
Connections that matter
Plate tectonics explains Himalayan convergence and regional activity.
India's drainage follows slopes, structures and depositional plains.
India's climate uses relief barriers and coastal position to explain rainfall contrasts.
Common mistakes
Interchanging Bhabar and Terai: porous coarse deposits and wetter re-emergent streams differ.
Calling khadar older alluvium: khadar is newer floodplain alluvium.
Saying the Eastern Ghats are more continuous: major rivers break their continuity.
Assigning coral origin to all Indian islands: the island groups have contrasting settings.
Revision checklist
I can distinguish structural and physiographic divisions.
I can compare Himalayan belts and regional sectors.
I can explain northern-plain subdivisions.
I can compare plateaux, Ghats and coastal plains.
I can locate desert and island features accurately.