📖 Introduction
India has a remarkably diverse relief — from the world's highest mountains (Himalayas) to vast alluvial
plains, ancient plateaus, coastal lowlands, and island arc systems. These five physiographic divisions give
India immense geographical variety and support different ways of life.
- India is the 7th largest country in the world (area: 3.29 million km²).
- Lies between latitudes 8°4'N and 37°6'N and longitudes 68°7'E and
97°25'E.
- India has five major physiographic (physical) divisions.
🏔️ PART 1: The Northern and North-Eastern Highlands (Himalayas)
Formation
- The Himalayas are fold mountains formed by the collision of the Indian tectonic plate
(moving northward) and the Eurasian tectonic plate about 50 million years ago — the
Tethys Sea floor was pushed up, forming the Himalayas.
- They are geologically young, fold mountains — still rising (earthquakes common in the
region due to tectonic activity).
Divisions (Three Parallel Ranges)
| Range |
Local Name |
Height |
Key Features |
| Greater (Outer) Himalayas |
Himadri |
Avg. 6,000 m; permanently snow-covered |
Highest range; Mt. Everest (8,848 m) world's highest; Kangchenjunga (8,586 m — India's highest);
Nanga Parbat; Nanda Devi; major glaciers (Gangotri, Siachen) |
| Middle Himalayas |
Himachal |
1,000–4,500 m |
Famous hill stations — Shimla, Mussoorie, Darjeeling, Nainital; terraced agriculture; fruit
growing |
| Outer Himalayas |
Shivalik (Sub-Himalayas) |
900–1,100 m |
Youngest, lowest range; fertile valleys (Duns) between Shivalik and Middle Himalayas — Dehradun
(most famous Dun); Dehra Dun is administrative centre of Uttarakhand |
Significance of the Himalayas
- Climatic barrier: Prevents bitterly cold Siberian winds from reaching Indian
subcontinent in winter. Forces SW Monsoon to rise and precipitate over India.
- Source of rivers: Perennial rivers (Indus, Ganga, Yamuna, Brahmaputra) originate from
Himalayan glaciers — provide water year-round for agriculture and drinking.
- Strategic barrier: Natural frontier between India and China/Central Asia.
- Tourism: Hill stations, trekking, pilgrimage (Char Dham: Badrinath, Kedarnath,
Gangotri, Yamunotri).
- Biodiversity: Rich forest ecosystems — from tropical to alpine.
🌾 PART 2: The Northern Plains (Indo-Gangetic Plain)
Formation
- Formed by the alluvial deposits brought down by Himalayan rivers (Ganga, Indus, Brahmaputra) over
millions of years into the depression between the Himalayas and the Peninsular Plateau.
- One of the world's largest and most fertile alluvial plains — covers about 7.5 lakh km² (750,000 km²).
Sub-Divisions
- Punjab Plains: Drained by five rivers of the Indus system (hence "Panch-Aab" = Punjab —
"land of five rivers": Jhelum, Chenab, Ravi, Beas, Satluj). Most of Punjab is now in Pakistan. Indian
Punjab drained by Satluj and Beas.
- Ganga Plains: Widest and most fertile section; drained by Ganga and its tributaries.
Includes UP, Bihar, and West Bengal (delta plains).
- Brahmaputra Plains: Assam; drained by the Brahmaputra.
Significance
- Most densely populated region of India — rich fertile alluvial soil, perennial water supply.
- "Granary of India" — produces most of India's food grains (wheat, rice, sugarcane).
- The Gangetic delta (Sundarbans) — world's largest river delta; rich in mangroves.
🏝️ PART 3: The Peninsular Plateau
Formation
- The oldest and most stable part of India — composed of ancient crystalline, igneous and metamorphic
rocks (Precambrian era — over 600 million years old).
- Made of the Gondwana landmass — part of the original supercontinent.
- Triangular in shape; apex pointing southward (Cape Comorin / Kanyakumari).
Sub-Divisions
| Sub-Division |
Key Feature |
| Deccan Plateau |
Highest part; west tilted (rivers flow eastward); basalt lava rock (Deccan Trap); black soil;
bounded by Western & Eastern Ghats |
| Chota Nagpur Plateau |
Jharkhand; ancient hard rocks; rich mineral deposits (coal, iron, copper, manganese); waterfall
country (Hundru, Dassam falls) |
| Central Highlands |
includes Malwa Plateau (MP), Bundelkhand (UP/MP); between Vindhyas and Narmada |
| Western Ghats |
Higher than Eastern Ghats; more continuous; UNESCO Biodiversity Hotspot; source of rivers
(Godavari, Krishna, Cauvery); western slope heavy rainfall (windward); eastern slope dry (rain
shadow) |
| Eastern Ghats |
Discontinuous, lower; cut by rivers; highest peak: Mahendragiri (Odisha, ~1,501 m). Runs
parallel to east coast. |
🌊 PART 4: Coastal Plains
| Coast |
Location |
Key Features |
| Western Coast |
Gujarat to Kerala along Arabian Sea |
Narrow plain (10–50 km wide); rich fishing; backwaters (Kerala); important ports (Mumbai, Kochi,
Goa); Konkan Coast (Maharashtra), Malabar Coast (Kerala) |
| Eastern Coast |
West Bengal to Tamil Nadu along Bay of Bengal |
Wider (50–100+ km); river deltas of Mahanadi, Godavari, Krishna, Cauvery; Coromandel Coast
(TN/AP); fertile delta agriculture (double/triple crop of rice); Chilika Lake (lagoon, Odisha)
|
🏝️ PART 5: Islands
| Islands |
Location |
Key Features |
| Andaman & Nicobar Islands |
Bay of Bengal; ~1,200 km from mainland |
Volcanic and coral islands; 572 islands (andaman = 38 inhabited, nicobar = 12 inhabited); Port
Blair = capital; Indira Point = southernmost tip of India (hit by 2004 Tsunami); rich tropical
evergreen forests |
| Lakshadweep Islands |
Arabian Sea; ~300 km from Kerala coast |
Coral islands (atolls and lagoons); 36 islands (only 11 inhabited); Kavaratti = capital;
world-class coral reefs; very small land area (~32 km²) |
📝 Quick Revision – Key Facts
| Physiographic Division |
Key Fact |
| Himalayas |
Young fold mountains; 3 parallel ranges (Himadri, Himachal, Shivalik); India's highest peak =
Kangchenjunga (8,586 m) |
| Northern Plains |
Alluvial; 7.5 lakh km²; most fertile; formed by Himalayan rivers; densely populated |
| Peninsular Plateau |
Oldest (Gondwana); crystalline rocks; Deccan Plateau (black soil/basalt); Chota Nagpur
(minerals) |
| Coastal Plains |
Western (narrow, Konkan/Malabar); Eastern (wider, deltas, Coromandel) |
| Islands |
A&N Islands (Bay of Bengal, volcanic/coral); Lakshadweep (Arabian Sea, coral atolls) |
📌 Chapter Summary
- India has 5 physiographic divisions: Northern Highlands (Himalayas), Northern Plains, Peninsular
Plateau, Coastal Plains, Islands.
- Himalayas: Young fold mountains; 3 ranges (Himadri=highest, Himachal=hill stations, Shivalik=lowest
+ Duns); pivotal for India's climate, rivers, and security.
- Northern Plains: Alluvial deposits of Himalayan rivers; world's most fertile and densely populated
plains.
- Peninsular Plateau: Oldest; Gondwana origin; Deccan Plateau (basalt/black soil); Chota Nagpur
(minerals); W.Ghats (biodiverse); E.Ghats (discontinuous).
- Coasts: Western (narrow, Konkan/Malabar) vs Eastern (wider, deltas, rice country). Islands: A&N
(Bay of Bengal), Lakshadweep (Arabian Sea).