Physical Geography of India

Overview

Physical Geography of India is a foundational topic in the Social Studies section of PSTET Paper II. Questions frequently test your knowledge of India's major landforms, river systems, climatic regions, and natural vegetation types. This topic connects directly to understanding India's agricultural patterns, population distribution, and resource base—themes that appear across geography, economics, and environmental studies.

For PSTET, expect direct factual questions (e.g., "Which river originates from Amarkantak?"), map-based reasoning (e.g., identifying mountain passes or river courses), and application questions linking physical features to human activities. Mastery requires memorising key facts while understanding the cause-effect relationships between landforms, climate, and vegetation.

Key Concepts

• **Physiographic Divisions**: India has six major physiographic divisions—the Himalayan Mountains, the Northern Plains, the Peninsular Plateau, the Coastal Plains, the Indian Desert (Thar), and the Islands (Andaman-Nicobar and Lakshadweep).

• **Young Fold Mountains vs Old Block Mountains**: The Himalayas are geologically young fold mountains (still rising), while the Aravallis, Vindhyas, and Satpuras are ancient, worn-down block mountains of the Peninsular Plateau.

• **River Systems**: India has two major drainage systems—Himalayan rivers (perennial, snow-fed like Ganga, Brahmaputra) and Peninsular rivers (rain-fed, seasonal like Godavari, Krishna, Narmada).

• **Monsoon Climate**: India's climate is dominated by the monsoon system. The southwest monsoon (June–September) brings 75% of annual rainfall; the retreating monsoon (October–November) affects Tamil Nadu coast.

• **Climatic Zones**: India experiences tropical, subtropical, arid, semi-arid, and alpine climates depending on latitude, altitude, and distance from the sea.

• **Natural Vegetation Zones**: Vegetation types correspond to rainfall and temperature—tropical rainforests (>200 cm rainfall), deciduous forests (70–200 cm), thorny scrub (<70 cm), and alpine vegetation (high altitudes).

• **Western and Eastern Ghats**: Western Ghats are higher, continuous, and receive heavy orographic rainfall; Eastern Ghats are lower, discontinuous, and cut by east-flowing rivers.

Formulas / Key Facts

| Category | Key Fact | |----------|----------| | Highest Peak | K2 (Godwin Austen) — 8,611 m (in India-administered region); Kangchenjunga — 8,586 m (entirely in India) | | Longest River | Ganga — 2,525 km | | Largest Peninsular River | Godavari — 1,465 km (also called "Dakshin Ganga") | | West-flowing Peninsular Rivers | Narmada and Tapi (flow through rift valleys) | | Northern Plains Formation | Alluvial deposits by Indus, Ganga, and Brahmaputra systems | | Thar Desert Location | Western Rajasthan; receives <25 cm annual rainfall | | Highest Rainfall | Mawsynram, Meghalaya — approx. 1,187 cm annually | | Monsoon Onset | Kerala coast — around 1st June | | Major Mountain Passes | Khyber, Bolan (NW); Shipki La, Bara Lacha La (Himachal); Nathu La (Sikkim) | | Andaman-Nicobar | 572 islands; highest point — Saddle Peak (732 m) |

Worked Examples

**Example 1: Identifying River Origin**

*Question*: The river Narmada originates from which location and flows in which direction?

*Solution*:

• Narmada originates from **Amarkantak Plateau** in Madhya Pradesh
• It flows **westward** through a rift valley between Vindhya and Satpura ranges
• It drains into the **Arabian Sea** near Bharuch, Gujarat
• Key distinction: Most peninsular rivers flow eastward; Narmada and Tapi are exceptions

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**Example 2: Linking Climate to Vegetation**

*Question*: Why does the Western Coast of India have tropical evergreen forests while the Deccan Plateau has deciduous forests?

*Solution*:

• Step 1: Western Coast receives **heavy orographic rainfall** (>200 cm) from southwest monsoon hitting the Western Ghats
• Step 2: High rainfall and humidity support **tropical evergreen forests** (dense, no leaf-shedding)
• Step 3: Deccan Plateau lies in the **rain shadow** of Western Ghats, receiving 70–150 cm rainfall
• Step 4: Moderate rainfall with a distinct dry season leads to **tropical deciduous forests** (trees shed leaves in dry season)

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**Example 3: Physiographic Division Identification**

*Question*: Arrange the following from north to south: Shiwaliks, Greater Himalayas, Lesser Himalayas.

*Solution*:

• Greater Himalayas (Himadri) — northernmost, highest (includes Everest, K2)
• Lesser Himalayas (Himachal) — middle range (includes Pir Panjal, Dhauladhar)
• Shiwaliks (Outer Himalayas) — southernmost, lowest, youngest
• Correct order: **Greater Himalayas → Lesser Himalayas → Shiwaliks**

Common Mistakes

• **Confusing Godavari with Ganga**: Students often confuse the largest peninsular river (Godavari) with the longest Indian river (Ganga). Remember: Ganga is longest overall; Godavari is longest among peninsular rivers.

• **Direction of Narmada and Tapi**: Many assume all peninsular rivers flow east. Narmada and Tapi flow westward through rift valleys—this is a frequent trap question.

• **Monsoon branch confusion**: The Bay of Bengal branch brings rain to northeast India and the Ganga plains; the Arabian Sea branch brings rain to the Western Coast. Students often reverse these.

• **Mixing up Western and Eastern Ghats**: Western Ghats are continuous and higher; Eastern Ghats are broken by rivers. Students incorrectly assume Eastern Ghats are continuous because of the longer coastline.

• **Himalayan range order**: Students sometimes place Shiwaliks in the north because "outer" suggests exterior. Remember: Outer means outer from India's perspective—Shiwaliks are closest to the plains.

Quick Reference

• **6 Physiographic Divisions**: Himalayas, Northern Plains, Peninsular Plateau, Coastal Plains, Thar Desert, Islands

• **Perennial vs Seasonal**: Himalayan rivers = perennial (snow-fed); Peninsular rivers = seasonal (rain-fed)

• **West-flowing exceptions**: Narmada, Tapi (rift valley rivers draining into Arabian Sea)

• **Monsoon months**: Southwest monsoon = June to September; Retreating monsoon = October to November

• **Rainfall-Vegetation link**: >200 cm = Evergreen; 70–200 cm = Deciduous; <70 cm = Thorny scrub

• **Highest rainfall station**: Mawsynram, Meghalaya (funnel-shaped hills trap monsoon winds)