India: Physiography (NCERT Geography Digest)

1. The Himalayas (young fold mountains)

Raised by the collision of the Indo-Australian and Eurasian plates (see geomorphology), the Himalayas run about 2400 km in an arc. Three parallel ranges north to south:

• Greater Himalayas (Himadri): the highest and most continuous range, with the loftiest peaks (Kanchenjunga is the highest in India; Everest lies in Nepal). Perennially snow-clad; the source of the great rivers.
• Lesser/Middle Himalayas (Himachal): ranges such as Pir Panjal, Dhauladhar and Mahabharat; the famous hill stations (Shimla, Mussoorie, Nainital) and valleys (Kashmir, Kangra, Kullu).
• Outer Himalayas (Shiwaliks): the lowest range, of recent unconsolidated sediment; the longitudinal valleys between Shiwaliks and the Lesser Himalayas are called Duns (Dehra Dun) or Duars.

Regionally, the Himalayas are divided (west to east) into Punjab/Kashmir, Kumaon (Garhwal), Nepal and Assam Himalayas. The Purvanchal (eastern hills: Patkai, Naga, Mizo, Manipur hills) curve southward along the eastern border.

2. The Northern Plains (Indo-Gangetic-Brahmaputra plain)

Formed by the alluvial deposits of the Indus, Ganga and Brahmaputra systems; extremely fertile and densely populated. Relief features:

• Bhabar: a narrow belt of coarse pebbles along the Shiwalik foot, where streams disappear underground.
• Terai: the re-emergence zone below the Bhabar, marshy and once forested.
• Bhangar: the older alluvium of the higher terraces, often containing calcareous kankar nodules.
• Khadar: the newer, fertile alluvium of the floodplains, renewed each year.

3. The Peninsular Plateau (the oldest landmass)

Made of ancient hard igneous and metamorphic rocks; rich in minerals. Two broad parts:

• Central Highlands (north of the Narmada): the Malwa Plateau, the Aravalli range (one of the oldest fold mountains, in Rajasthan), the Vindhya and Bundelkhand uplands.
• Deccan Plateau (south of the Narmada): bordered by the Western Ghats (Sahyadri, continuous, higher; passes at Thal, Bhor and Pal Ghat) and the Eastern Ghats (discontinuous, lower, dissected by rivers). The two meet in the Nilgiri Hills. Anaimudi (in the Western Ghats, Kerala) is the highest peak in peninsular India. The Deccan Trap is a vast basaltic flood-basalt province (source of black regur soil).

4. The Indian Desert (Thar)

To the west of the Aravallis in Rajasthan; an arid landscape of sand dunes (barchans), low rainfall (below 150 mm), and ephemeral streams; the Luni is the only significant river.

5. The Coastal Plains

• Western Coastal Plain: narrow, between the Western Ghats and the Arabian Sea; segments are the Konkan, the Kanara and the Malabar coast; marked by lagoons (kayals) in Kerala. It is a submergent coast with good natural harbours (Mumbai, Marmagao, Kochi).
• Eastern Coastal Plain: broad and level, between the Eastern Ghats and the Bay of Bengal; built by the deltas of the Mahanadi, Godavari, Krishna and Kaveri; the northern part is the Northern Circars, the southern the Coromandel coast. Chilika Lake (Odisha) is the largest brackish-water lagoon in India.

6. The Islands

• Andaman and Nicobar Islands (Bay of Bengal): of tectonic and volcanic origin; Barren Island is India's only active volcano; Indira Point is the southernmost point of India.
• Lakshadweep (Arabian Sea): small coral (atoll) islands.

The security and human-rights angle

India's physiography defines its border challenges and the CAPF deployment map: the high-altitude Himalayan frontier (ITBP), the Thar and the riverine plains of the western and eastern borders (BSF), and the strategic island chains in the Bay of Bengal and Arabian Sea. The fragile ecology of the Himalayas and the Western Ghats (a biodiversity hotspot) ties physiography to environmental governance and disaster management.

How CAPF asks this

• The three ranges of the Himalayas (Himadri, Himachal, Shiwalik) and the Dun valleys. Bhabar, Terai, Bhangar, Khadar in order.
• Highest peak in India (Kanchenjunga) and in peninsular India (Anaimudi). Continuous Western versus discontinuous Eastern Ghats and their meeting at the Nilgiris.
• Barren Island (active volcano), Indira Point (southernmost), and coral Lakshadweep.

Authored practice

1. Arrange from the Shiwalik foot inward: Terai, Bhabar, Khadar, Bhangar (by relief sequence from the mountains to the floodplain). (Answer: Bhabar, Terai, Bhangar, Khadar.) Authored practice, not a verbatim PYQ.
2. The highest peak in peninsular India is: (a) Doddabetta (b) Anaimudi (c) Mahendragiri (d) Guru Shikhar. Answer: (b) Anaimudi. Authored practice, not a verbatim PYQ.