Physical Geography of India

Overview

Physical Geography of India is a foundational topic for WB TET Paper II Social Studies. It covers the structural framework of the Indian subcontinent — the mountains that guard it, the plains that feed it, the rivers that sustain it, and the climate and vegetation that define its ecological diversity. Questions typically test factual recall (names, locations, heights, lengths) and the ability to connect physical features with human activities like agriculture, settlement and transportation.

For the TET exam, you must know the major physiographic divisions, the course and tributaries of principal rivers, the mechanism of the Indian monsoon, and the distribution of natural vegetation types. Map-based mental images are essential — examiners often ask "which state" or "which direction" questions that require spatial awareness.

Key Concepts

• **Six Major Physiographic Divisions**: India is divided into the Himalayan Mountains, Northern Plains, Peninsular Plateau, Indian Desert, Coastal Plains and Islands. Each has distinct geological origin and landforms.

• **Himalayan Zones**: The Himalayas run west to east and comprise three parallel ranges — the Greater Himalayas (Himadri), Lesser Himalayas (Himachal) and Outer Himalayas (Shiwaliks). Important passes include Khyber, Bolan, Shipki La and Nathu La.

• **Northern Plains Formation**: Formed by alluvial deposits of the Indus, Ganga and Brahmaputra river systems. Sub-divisions are Bhabar (pebble zone), Terai (marshy), Bhangar (old alluvium) and Khadar (new alluvium).

• **Peninsular Plateau Characteristics**: One of the oldest landmasses, made of igneous and metamorphic rocks. Divided into the Central Highlands (north of Narmada) and the Deccan Plateau (south of Narmada). The Western Ghats are higher and continuous; Eastern Ghats are broken and lower.

• **Drainage Systems**: Himalayan rivers are perennial (snow-fed); Peninsular rivers are seasonal (rain-fed). West-flowing rivers (Narmada, Tapi) form estuaries; east-flowing rivers (Godavari, Krishna, Kaveri) form deltas.

• **Monsoon Mechanism**: India's climate is dominated by the south-west monsoon (June–September) bringing 75% of annual rainfall, and the retreating north-east monsoon (October–December) important for Tamil Nadu.

• **Natural Vegetation Zones**: Distributed based on rainfall and temperature — Tropical Evergreen (>200 cm rain), Tropical Deciduous (75–200 cm), Thorn Forests (<75 cm), Montane Forests (altitude-based) and Mangroves (tidal areas).

Key Facts

| Category | Must-Remember Facts | |----------|---------------------| | Highest Peak | K2 (Godwin Austen) — 8611 m (in India-administered region); Kanchenjunga — 8586 m (entirely within India) | | Longest River | Ganga — 2525 km | | Largest River by Discharge | Brahmaputra | | Highest Plateau | Ladakh Plateau (average 5000 m) | | Largest Peninsular River | Godavari — 1465 km ("Dakshin Ganga") | | Western Ghats Highest Peak | Anai Mudi — 2695 m (Kerala) | | Eastern Ghats Highest Peak | Mahendragiri — 1501 m (Odisha) | | Monsoon Arrival | Kerala coast — 1st June (normal date) | | Sundarbans Location | Ganga-Brahmaputra delta, West Bengal — largest mangrove forest in the world | | Rain-Shadow Region | Eastern slopes of Western Ghats (e.g., interior Karnataka, western Tamil Nadu) |

**River Tributaries to Remember**:

• Ganga: Yamuna, Ghaghara, Gandak, Kosi, Son
• Brahmaputra: Dibang, Lohit, Subansiri, Teesta
• Godavari: Pranhita, Indravati, Manjra

Worked Examples

**Example 1: Identifying Physiographic Division**

*Question*: The Malwa Plateau is part of which physiographic division?

*Solution*: 1. Malwa Plateau lies north of the Narmada River in Madhya Pradesh and Rajasthan. 2. The region north of Narmada within the Peninsular Plateau is called the Central Highlands. 3. **Answer**: Central Highlands (part of Peninsular Plateau).

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**Example 2: River System Classification**

*Question*: Why does the Narmada form an estuary while the Godavari forms a delta?

*Solution*: 1. Narmada flows through a rift valley with hard rocky bed — carries less sediment. 2. It flows westward into the Arabian Sea through a narrow valley — strong tidal currents wash away deposits. 3. Godavari flows eastward across a gentler gradient, carrying more alluvium, and deposits it at the Bay of Bengal where tidal action is weaker. 4. **Answer**: Narmada flows through a rift valley with less sediment and stronger tidal action; Godavari flows on a gentler slope with more sediment and weaker tides.

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**Example 3: Monsoon and Vegetation Link**

*Question*: Which type of natural vegetation is found in areas receiving 75–200 cm annual rainfall?

*Solution*: 1. Tropical Evergreen forests need >200 cm rainfall. 2. Thorn and Scrub forests occur in <75 cm rainfall areas. 3. The intermediate zone (75–200 cm) supports Tropical Deciduous forests — trees shed leaves in dry season. 4. **Answer**: Tropical Deciduous Forests (Monsoon Forests).

Common Mistakes

• **Confusing Himadri with Himachal**: Students mix up the three Himalayan ranges. Remember: Himadri = Greater = highest and northernmost; Himachal = Lesser = middle range with hill stations like Shimla; Shiwaliks = Outer = southernmost and youngest.

• **Mixing up Bhabar and Terai**: Bhabar is the pebble-stone zone where streams disappear underground. Terai is the marshy, forested belt where those streams re-emerge. Order from north to south: Bhabar → Terai → Bhangar/Khadar.

• **Assuming all Peninsular rivers flow eastward**: Narmada and Tapi are major exceptions — they flow westward through rift valleys. This is a frequently asked fact.

• **Forgetting the October–December monsoon**: Students focus only on the south-west monsoon. The north-east (retreating) monsoon is crucial for Tamil Nadu's winter rice crop — it brings rain to the Coromandel Coast.

• **Placing Western Ghats in the wrong states**: Western Ghats run through Gujarat, Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu. They do NOT touch Odisha or Andhra Pradesh — those states have the Eastern Ghats.

Quick Reference

• **Three Himalayan Ranges (N→S)**: Himadri – Himachal – Shiwaliks
• **Four Northern Plain Zones (N→S)**: Bhabar – Terai – Bhangar – Khadar
• **West-Flowing Peninsular Rivers**: Narmada, Tapi (form estuaries)
• **South-West Monsoon**: Arabian Sea branch + Bay of Bengal branch; June–September
• **Tropical Deciduous = Monsoon Forests**: Teak, Sal, Bamboo; 75–200 cm rainfall
• **Sundarbans**: World's largest mangrove; Royal Bengal Tiger habitat; West Bengal