Physical Features of India

1. Major Physiographic Divisions — Overview

India's relief features are extremely varied — from snow-capped mountains and fertile plains to rocky plateaus, sandy deserts, and coastal lowlands. The country can be divided into six broad physiographic divisions (NCERT groups the Islands as a seventh):

1. The Himalayan Mountains
2. The Northern Plains
3. The Peninsular Plateau
4. The Indian Desert
5. The Coastal Plains
6. The Islands

Geological history: Millions of years ago, a large landmass called Gondwana Land existed in the southern hemisphere. It included the present-day peninsular India, Australia, South America and Africa. About 225 million years ago, this supercontinent began to break up. The Indian plate drifted northward and collided with the Eurasian plate, pushing up the sediments of the ancient Tethys Sea to form the Himalayas. The depression left behind gradually filled with alluvium brought by rivers — this became the Northern Plains.

Geologically, India has three broad structural units:

• The Peninsular Block — oldest, stable, made of ancient rocks.
• The Himalayas and other young fold mountains — newest, still rising.
• The Indo-Gangetic Plain — formed by river deposits between the two units above.

2. The Himalayan Mountains

The Himalayas are the youngest and highest fold mountains in the world, stretching over 2,400 km from west to east between the Indus Gorge (near Nanga Parbat) in the west and the Brahmaputra Gorge (near Namcha Barwa) in the east. Their width varies from 400 km in Kashmir to 150 km in Arunachal Pradesh. They form a great arc running from west to east.

Three Parallel Ranges (North to South)

Important Peaks

• Mt Everest — 8,848 m (Nepal); highest peak in the world; also called Sagarmatha (Nepal) / Chomolungma (Tibet).
• K2 (Godwin Austen) — 8,611 m; in Karakoram range; second highest in the world.
• Kanchenjunga — 8,598 m; on India-Nepal border; India's highest peak within its territory (Sikkim).
• Nanga Parbat — 8,126 m; western anchor of the Himalayas.
• Namcha Barwa — 7,756 m; eastern anchor of the Himalayas.

Important Passes

• Karakoram Pass — Ladakh; connects India to China (Xinjiang); one of the highest road passes in the world.
• Zoji La — Jammu and Kashmir; connects Srinagar to Leh (Ladakh).
• Shipki La — Himachal Pradesh; River Sutlej enters India through this pass.
• Nathu La / Jelep La — Sikkim; historic trade route to Tibet and China.
• Bomdi La — Arunachal Pradesh; strategic pass near the China border.

Regional Divisions Based on Rivers

The Himalayas are divided into regional sections based on location between major rivers:

• Punjab Himalayas — between the Indus and Satluj (500 km).
• Kumaon Himalayas — between the Satluj and Kali (320 km).
• Nepal Himalayas — between the Kali and Tista (800 km); contains Mt Everest.
• Assam Himalayas — between the Tista and Dihang (720 km).

The rivers Indus, Ganga, Brahmaputra and their tributaries are antecedent rivers — older than the mountains themselves; they cut deep gorges through the ranges as the mountains rose.

Significance of the Himalayas

• Climatic barrier: prevent cold Central Asian winds from entering India; force south-west monsoon winds to give heavy rainfall on the Indian subcontinent.
• Source of perennial rivers: glaciers like Gangotri, Siachen, and Zemu feed rivers all year round.
• Biodiversity: unique flora and fauna at different altitudinal zones.
• Strategic defence: natural boundary on the northern frontier.
• Mineral and forest resources: forests in the Shiwalik and Himachal ranges.

3. The Northern Plains

The Northern Plains lie to the south of the Himalayas and north of the Peninsular Plateau, extending over about 7 lakh sq km. They stretch from Punjab in the west to the Brahmaputra valley in the east — approximately 2,400 km long and 240–320 km wide. Formed by the interplay of the three river systems — Indus, Ganga and Brahmaputra — and their tributaries, the plains consist of deep alluvial soil, in some places up to 1,000–2,000 m in depth.

Four Zones of the Northern Plains

Regional Divisions of Northern Plains

• Punjab Plains — western part; formed by Indus and its five tributaries; doabs (land between two rivers) — Bari, Bist, Rachna, Chaj, Sindh Sagar.
• Ganga Plains — stretches from the Ghaggar in the west to the Teesta in the east; most extensive part; covers UP, Bihar, parts of Jharkhand and West Bengal.
• Brahmaputra Plains — in Assam; floodplain of the Brahmaputra; prone to annual flooding; forms one of the most fertile regions.

Significance

• World's largest and most fertile alluvial plain — formed over millions of years.
• Most densely populated region of India.
• Supports rice, wheat, sugarcane, pulses — India's food bowl.
• Level terrain, fertile soil, and abundant river water make it ideal for intensive mechanised farming.

4. The Peninsular Plateau

The Peninsular Plateau is a tableland composed of old crystalline, igneous and metamorphic rocks. It is one of the oldest and most stable landmasses of India — a remnant of Gondwana Land. It is broadly divided into two parts: the Central Highlands (north of the Narmada) and the Deccan Plateau (south of the Narmada).

Central Highlands

• Located north of the Narmada river; forms part of the Malwa Plateau.
• Bounded by the Aravalli range in the north-west and the Vindhyan range in the south.
• Rivers — Chambal, Sind, Betwa, Ken — flow from south-west to north-east (toward Ganga).
• Chota Nagpur Plateau — mineral-rich extension in Jharkhand; rich in coal, iron ore, manganese, bauxite — called the "mineral heartland of India".
• Extends eastward into the Meghalaya plateau (Garo, Khasi, Jaintia hills).

Deccan Plateau

• Triangular landmass south of the Narmada and Satpura ranges.
• Higher in the west (close to Western Ghats) and slopes gently eastward — hence most Peninsular rivers flow east into the Bay of Bengal.
• The Western Ghats form the steep western edge; the Eastern Ghats form the broken eastern margin.
• The north-western part — Deccan Trap — covered by black lava-based soil called regur (black soil); excellent for cotton cultivation.

Western Ghats (Sahyadri)

• Run parallel to the west coast for about 1,600 km — a continuous, unbroken range.
• Highest in the south: Anai Mudi (2,695 m) in the Anamalai Hills, Kerala — highest peak of Peninsular India.
• Doda Betta (2,637 m) in the Nilgiris (Tamil Nadu) — second highest.
• Act as a barrier to south-west monsoon — western slopes receive very heavy orographic rainfall; eastern slopes are in the rain shadow.
• Key passes: Thal Ghat (Mumbai-Nashik route), Bhor Ghat (Mumbai-Pune route), Pal Ghat (Palakkad Gap) — connects Kerala to Tamil Nadu.

Eastern Ghats

• Discontinuous, irregular hill ranges along the eastern coast; from Mahanadi to Nilgiris.
• Cut through by rivers — Mahanadi, Godavari, Krishna, Kaveri — that flow east into the Bay of Bengal.
• Average height: 600 m; Mahendra Giri (1,501 m) — highest peak of Eastern Ghats (Odisha-Andhra Pradesh border).
• Much lower and less continuous than the Western Ghats.

5. The Indian Desert (Thar Desert)

The Thar Desert (Great Indian Desert) lies to the north-west of the Aravalli Hills, covering large parts of Rajasthan and extending into Gujarat, Haryana and Punjab. It is an arid region receiving less than 150 mm of rainfall per year.

• The desert is characterised by sand dunes, especially barchans — crescent-shaped dunes formed when wind blows consistently from one direction; the horns of the crescent point downwind.
• Luni is the only large river in the region; originates near Ajmer, flows south-west into the Rann of Kachchh; becomes saline in its lower course; does not reach the sea.
• Other streams are ephemeral (seasonal) — they dry up before reaching the sea.
• Vegetation is sparse: thorny bushes, cacti, drought-resistant plants.
• Wildlife: Indian gazelle (chinkara), blackbuck, desert fox, Indian bustard.
• The Rann of Kachchh — a large seasonal salt marsh — forms part of the southern boundary.

6. The Coastal Plains

India has a coastline of about 7,516.6 km. Narrow coastal strips on either side of the Peninsular Plateau form the Coastal Plains. They are divided into the West Coast and the East Coast.

West Coast

Lies between the Western Ghats and the Arabian Sea; generally narrow (10–25 km); submerged coast — no major deltas; receives heavy rainfall from the south-west monsoon.

• Malabar Coast (southern section — Kerala and southern Karnataka): features kayals (backwaters) — lagoons separated from the sea by sand bars; used for fishing, transport, tourism; famous examples: Vembanad Lake, Ashtamudi Lake.
• Konkan Coast (central section — Maharashtra and Goa): rocky, rugged shoreline; natural harbours including Mumbai.
• Kannad Plain (Karnataka) and Gujarat Plain (including the Rann of Kachchh) form the northern sections.

East Coast

Lies between the Eastern Ghats and the Bay of Bengal; wider (100–130 km); emergent coast — large river deltas formed by eastward-flowing Peninsular rivers.

• Coromandel Coast (southern section — Tamil Nadu and southern Andhra Pradesh): receives rainfall mainly from the North-East (retreating) Monsoon in October–December — opposite to most of India.
• Northern Circar / Utkal Plains (northern section — coastal Andhra Pradesh and Odisha): large deltas of Mahanadi, Godavari, Krishna, Kaveri rivers.
• Chilika Lake (Odisha) — largest lake / coastal lagoon in India.
• Pulicat Lake — on Andhra Pradesh-Tamil Nadu border.

Comparison: West Coast vs East Coast

7. The Islands

India has two major island groups — Lakshadweep Islands in the Arabian Sea and Andaman and Nicobar Islands in the Bay of Bengal — plus many smaller islands along the coast.

Lakshadweep Islands

• A group of small coral islands — formed by the accumulated skeletons of tiny marine organisms called coral polyps.
• Located about 200–300 km off the Kerala coast; total area only 32 sq km — smallest Union Territory.
• Comprises 36 islands; only 11 are inhabited. Kavaratti is the administrative capital.
• Surrounded by coral reefs — critical ecological feature; vulnerable to rising sea levels and bleaching.
• Rich in marine biodiversity: sea turtles, dolphins, reef fish. Famous for coconut plantations.
• Formerly called the Laccadive, Minicoy and Amindivi Islands; renamed Lakshadweep in 1973.
• Nearest to the island of Minicoy which is close to the Maldives.

Andaman and Nicobar Islands

• Elongated chain of islands in the Bay of Bengal; larger and more numerous than Lakshadweep; area 8,249 sq km.
• Of volcanic / tectonic origin; geologically an extension of the Arakan Yoma mountain ranges of Myanmar.
• Two groups: Andaman in the north (larger) and Nicobar in the south; separated by the Ten Degree Channel (at 10 degrees N latitude).
• Port Blair is the capital (on South Andaman Island).
• Barren Island — India's only active volcano and the only confirmed active volcano in South Asia.
• Narcondam Island — dormant volcano.
• Dense tropical rainforests; rich biodiversity; home to rare endemic species.
• Indigenous tribal communities: Andamanese, Onge, Jarawa, Sentinelese (Andaman); Nicobarese (Nicobar).
• Strategic location near the Strait of Malacca — important for India's naval and maritime interests.
• Comprise 572 islands, islets, and rocks; about 38 are inhabited.

Comparison: Lakshadweep vs Andaman and Nicobar

8. Solved NCERT Exercise Questions

Q1(i). A landmass bounded by sea on three sides is referred to as:
(a) Coast   (b) Island   (c) Peninsula   (d) Strait
Answer: (c) Peninsula. India is a classic peninsula — bounded by the Arabian Sea in the west, the Bay of Bengal in the east, and the Indian Ocean in the south.

Q1(ii). Mountain ranges in the eastern part of India forming its boundary with Myanmar are collectively called:
(a) Himachal   (b) Uttarakhand   (c) Purvachal   (d) None of the above
Answer: (c) Purvachal. These include the Patkai Hills, Naga Hills, Manipur Hills, and Mizo Hills — forming India's north-eastern boundary with Myanmar.

Q1(iii). The western coastal strip, south of Goa is referred to as:
(a) Coromandel   (b) Kannad   (c) Konkan   (d) Northern Circar
Answer: (b) Kannad. The Kannad Plain lies south of Goa in Karnataka along the west coast. (Konkan is north of Goa, in Maharashtra.)

Q1(iv). The highest peak in the Eastern Ghats is:
(a) Anai Mudi   (b) Kanchenjunga   (c) Mahendra Giri   (d) Khasi
Answer: (c) Mahendra Giri at 1,501 m. Anai Mudi (2,695 m) is in the Western Ghats; Kanchenjunga is in the Himalayas.

Q2(i). What is the bhabar?
Bhabar is a narrow, pebble-studded plain lying along the foothills of the Shiwalik ranges. All rivers coming down from the Himalayas deposit their coarse sediments here and then disappear underground because the soil is very porous. It is about 8–16 km wide. It is unsuitable for cultivation but some large trees grow here.

Q2(ii). Name the three major divisions of the Himalayas from north to south.
(1) The Greater Himalayas (Himadri) — northernmost, highest, average altitude over 6,000 m; all highest peaks; permanently snow-covered.
(2) The Lesser Himalayas (Himachal) — middle range, 1,000–4,500 m; famous hill stations; Kashmir and Kangra valleys.
(3) The Shiwaliks (Sub-Himalaya) — southernmost, lowest range, 900–1,100 m; formed of unconsolidated sediments; duns between Shiwaliks and Himachal.

Q2(iii). Which plateau lies between the Aravalli and the Vindhyan ranges?
The Malwa Plateau, which is part of the Central Highlands of the Peninsular Plateau, lies between the Aravalli Hills in the north-west and the Vindhyan range in the south.

Q2(iv). Name the island group of India having coral origin.
Lakshadweep Islands in the Arabian Sea. They are formed from the accumulated skeletons of tiny marine organisms called coral polyps, and are surrounded by coral reefs.

Q3. Distinguish between Bhangar and Khadar.
Bhangar: Older alluvium; found in upland areas away from river flood plains; slightly higher in elevation; less fertile; may contain kankar (calcium carbonate nodules) and pebbles.
Khadar: Newer, finer alluvium; found in the active flood plains along river channels; replenished by flood deposits every year; very fertile and ideal for agriculture; forms the most productive zone of the Northern Plains.

Q4. Why is the Deccan Plateau higher in the west and lower in the east?
The Deccan Plateau tilts from west to east. The Western Ghats form a high, steep escarpment on the western side while the Eastern Ghats are lower and discontinuous. Because the plateau is higher in the west, all major Peninsular rivers — Mahanadi, Godavari, Krishna, and Kaveri — flow from west to east and drain into the Bay of Bengal. The western coastal strip is therefore narrow while the eastern coastal plain is broader.

Q5. Why do rivers of Peninsular India not form deltas on the west coast?
The rivers flowing down the west coast are short, swift and steep-gradient because the Western Ghats run close and parallel to the coast. They rush down quickly and directly into the Arabian Sea through narrow valleys, carrying very little sediment — not enough to form deltas. By contrast, eastward-flowing rivers are much longer, carry abundant sediment, and slow down on the broad coastal plains before reaching the Bay of Bengal, thus forming large deltas.