Physiographic Divisions of India

Subject: Geography | Unit: Physical Geography | Topic: Physiographic Divisions Exam: AP Group 2 (APPSC)

Introduction

India's landmass spans 32.8 lakh sq km with extraordinary physical diversity — from the world's youngest and highest mountain chain in the north to ancient peninsular plateaus in the south, from scorching deserts in the west to lush islands in the east. Understanding the six major physiographic divisions is foundational for geography, as they determine India's climate, drainage, soils, vegetation, agriculture, and settlement patterns. This topic is a perennial favourite in APPSC exams, with questions on mountain passes, peaks, plains subdivisions, and coastal features.

Context

India's physical geography results from two geological events: (1) the breakup of Gondwanaland, which gave us the ancient Peninsular Plateau, and (2) the collision of the Indian Plate with the Eurasian Plate (~50 million years ago), which created the Himalayas and, through their erosion, the Northern Plains. The Tropic of Cancer (23.5 deg N) divides India into almost equal halves, influencing the climate of each physiographic zone.

Core Content

The Six Major Physiographic Divisions

Land Area Distribution

The Himalayas

• Length: ~2,500 km (Indus gorge to Brahmaputra gorge)
• Width: 160-400 km
• Three parallel ranges running west to east:

Key Peaks of India

Important Mountain Passes

Longitudinal Divisions of Himalayas

Northern Plains

• Length: ~3,200 km (east to west); Width: 150-300 km
• Alluvium depth: 1,000-2,000 m
• Formed by depositional work of Indus, Ganga, Brahmaputra rivers

Regional Plains: Punjab Plains (Doabs between Indus tributaries), Ganga Plains (largest — UP, Bihar, WB), Brahmaputra Plains (Assam valley, flood-prone).

Peninsular Plateau

• Oldest landmass (Gondwana remnant); largest physiographic division (~16 lakh sq km, ~50% of India)
• Elevation: 600-900 m; composed of igneous and metamorphic rocks; triangular shape

Central Highlands (north of Narmada): Malwa Plateau, Bundelkhand, Baghelkhand; Vindhya Range forms northern boundary (300-650 m); rivers Chambal, Sind, Betwa, Ken flow north to Ganga.

Deccan Plateau (south of Narmada): Higher in west, slopes gently eastward; bordered by Western Ghats (west) and Eastern Ghats (east); sub-plateaus: Chotanagpur (mineral-rich), Karnataka, Maharashtra.

Western Ghats vs Eastern Ghats

Other Important Ranges

Indian Desert (Thar)

• Area: ~2,00,000 sq km; 85% in India, 15% in Pakistan
• ~4.5% of India's total area; world's 18th largest desert, 9th largest hot subtropical desert
• Rainfall: 100-500 mm annually
• Features: sand dunes (barchans), playas (dhands), Luni river (only river)

Coastal Plains

Total Indian coastline: 7,517 km; Peninsular coastline: ~6,100 km

Western Coastal Plain (width ~50 km; submerged coastline — estuaries, no deltas):

Eastern Coastal Plain (width 100-130 km; emergent coastline — deltas, lagoons):

Islands

Andaman and Nicobar: ~572 islands; separated by 10 Degree Channel; Saddle Peak (737 m) highest; Barren Island — India's only active volcano; Indira Point — southernmost point of India.

Lakshadweep: 36 islands (10 inhabited); coral atolls; total area 32 sq km; smallest UT of India; 280-480 km off Kerala coast.

AP Connection

• AP lies in the Peninsular Plateau region with the Eastern Ghats traversing through it
• Key hill ranges in AP: Nallamala, Velikonda, Seshachalam, Palakonda, Ananthagiri
• Coastal plains of AP (Andhra Plain/Circars) are among the widest in India — the Godavari and Krishna deltas are immensely fertile
• Ananthagiri Hills near Araku Valley in Visakhapatnam district is a significant hill station area
• Seshachalam Hills house the Tirumala temple and are a UNESCO Biosphere Reserve
• Jindhagada Peak (~1,690 m) in Alluri Sitharama Raju district is the highest point in AP

Key Points Summary

1. India has 6 major physiographic divisions: Mountains, Plains, Plateau, Desert, Coastal Plains, Islands
2. Plains cover the largest area (43.2%) while mountains cover the least (10.6%)
3. Himalayas have 3 parallel ranges: Himadri (Great), Himachal (Lesser), Shiwaliks (Outer)
4. K2 (8,611 m) is the highest peak in Indian territory; Kanchenjunga (8,586 m) is highest within India proper
5. Northern Plains are divided into Bhabar, Terai, Bhangar, and Khadar zones
6. Bhangar = old alluvium with kankar; Khadar = new alluvium, most fertile
7. Peninsular Plateau is the largest division (~50% of India's area) and the oldest landmass
8. Central Highlands lie north of Narmada; Deccan Plateau south of Narmada
9. Western Ghats are higher (~1,500 m) and continuous; Eastern Ghats are lower (~600 m) and discontinuous
10. Western coast has estuaries (submerged); Eastern coast has deltas (emergent)
11. Aravalli is among the world's oldest fold mountains; separates Thar from rest of India
12. Thar Desert covers ~4.5% of India; Luni is the only river
13. Andaman & Nicobar has India's only active volcano (Barren Island)
14. Lakshadweep is India's smallest UT; made of coral atolls
15. India's total coastline is 7,517 km
16. In AP, the Eastern Ghats include Nallamala, Seshachalam, Velikonda, and Palakonda ranges
17. Jindhagada Peak (~1,690 m) is the highest point in Andhra Pradesh

Exam Strategy

• Table-based questions are very common: memorize the passes table, peaks table, and plains subdivisions
• Comparison questions: Western Ghats vs Eastern Ghats, Bhangar vs Khadar, Western coast vs Eastern coast
• AP-specific: Know the hill ranges in AP, especially Seshachalam (Biosphere Reserve) and Nallamala (Tiger Reserve)
• Trick questions: Peninsular Plateau is the LARGEST division by area (not the Northern Plains); K2 is technically in PoK
• For match-the-following: associate passes with states (Nathu La = Sikkim, Shipki La = Himachal, Bomdila = Arunachal)

Key Terms Glossary