Indian Geography & Environment
🟢 Lite — Quick Review (1h–1d)
Himalayas — Three Parallel Ranges
- Greater Himalayas (Himadri): Highest, continuous; Everest (8,849m), K2 (8,611m in Karakoram), Kangchenjunga (8,586m); home to holy shrines (Gaumukh, Amarnath)
- Lesser Himalayas (Himachal): 2,000–4,500m; major hill stations (Shimla, Mussoorie, Nainital, Darjeeling); flanked by valleys (Kashmir, Kangra)
- Sub-Himalayas (Shiwaliks): 1,000–1,500m; Dun valleys (Dehradun, Kotli); geologically youngest, composed of unconsolidated sediments
Indo-Gangetic Plain
- Created by Indus, Ganga, Brahmaputra river systems over millions of years
- Three divisions: Rajasthan Plain (Thar Desert, inland drainage), Punjab-Haryana Plain (Five Rivers — Satluj, Beas, Ravi, Sutlej, Ghaggar;Bhakra Nangal Project), Ganga Plain (most populous; alluvial soil)
- Alluvial soil: Khadar (new, sandy, frequent floods) and Bhangar (old, clayey,calcareous; older alluvium with kankar nodules)
- Indogangetic divides into: Western, Central, Eastern parts; deltaic region (Sunderbans — largest delta, mangrove forest; tiger reserve)
Peninsular India
- Plateau: Deccan Plateau (ancient landmass, volcanic basalt), Chota Nagpur Plateau (rich in minerals — mica, coal, iron ore, copper; Jharkhand), Malwa Plateau (Narmada-Son-Damodor rivers; bounded by Vindhyas and Satpuras)
- Mountain ranges: Western Ghats (Sahyadris; 1,600 km; UNESCO Western Ghats as biodiversity hotspot; 7 World Heritage Sites); Eastern Ghats (discontinuous; rich in minerals; Koraput, Visakhapatnam)
- Western Ghats vs Eastern Ghats: Western higher (avg 900-1,500m), continuous; Eastern lower, fragmented; both biogeographically distinct
- Major rivers: Narmada (west-flowing, into Gulf of Khambhat; tars), Tapti, Mahanadi, Godavari (560 km delta; East Godavari, West Godavari), Krishna, Kaveri (Cauvery)
Monsoons & Climate
- Mechanism: Differential heating of land and sea; Inter-Tropical Convergence Zone (ITCZ); subtropical westerly jet; tropical easterly jet
- South-West Monsoon (June-September): 80% of India’s rainfall; Arabian Sea branch (hits Western Ghats → heavy rainfall, e.g., Mahabaleshwar); Bay of Bengal branch (strikes NE India → Cherrapunji, Mawsynram 12,000 mm; enters Ganga plain)
- North-East Monsoon (October-November): Retreating monsoon; coastal Tamil Nadu receives rainfall; cyclones in Bay of Bengal
- El Niño: warming of Pacific; weakens monsoon; La Niña: strengthens monsoon
Natural Vegetation & Wildlife
- Tropical Evergreen (Assam, Western Ghats — >200 cm rainfall); Tropical Deciduous/Monsoon (most common, 100-200 cm rainfall); Thorny (Rajasthan, Gujarat, Punjab — <75 cm rainfall); Mangrove (Sunderbans, Bhitarkanika — tidal swamps); Alpine (Himalayan slopes — temperate to alpine)
- National Parks: Jim Corbett (Uttarakhand, first; tigers); Kaziranga (Assam, one-horned rhinoceros); Periyar (Kerala, elephants); Ranthambore (Rajasthan, tigers); Bandipur (Karnataka); Gir (Gujarat, Asiatic lions)
- Biosphere Reserves: 18 UNESCO designated; Nilgiri (first, 1986); Sundarbans; Nanda Devi; Nokrek; Pachmarhi; Similipal; etc.
⚡ Exam Tip: AILET focuses on location-based questions, numerical values (heights, lengths, rainfall), and environmental issues. Be ready for questions on biosphere reserves, national parks with their flagship species, and monsoon mechanisms.
🟡 Standard — Regular Study (2d–2mo)
Physical Divisions of India India occupies 7th position globally (area: 32,87,263 sq km); 2nd in population; diverse physical features:
- Himalayan Mountains: Tectonically active (印-Burma plate collision); prone to earthquakes; glacial lakes (e.g., GLOFs — glacial lake outburst floods)
- Indo-Gangetic-Brahmaputra Plain: Foredeep; world’s most densely populated region; fertile alluvial soil; three major river systems
- Peninsular Plateau: Part of Gondwanaland; stable landmass; mineral-rich; basaltic lava flows (Deccan Traps)
- Indian Desert: Thar; sand dunes; arid climate; inland drainage (Luni river)
- Coastal Plains: Eastern (Coromandel — Bay of Bengal; lagoons, deltas; Odisha, Andhra, Tamil Nadu) vs Western (Konkan — Arabian Sea; steep, narrow; Goa to Gujarat; backwaters — Kerala)
- Islands: Andaman & Nicobar (Bay of Bengal; active volcano — Barren Island; Indira Point — southernmost point); Lakshadweep (Arabian Sea; atolls; coral reefs; Kavaratti)
Major River Systems
Himalayan Rivers (Perennial)
- Indus: Source: Kailash Mansarovar (Tibet); enters India via Ladakh; 5 tributaries in Punjab (Jhelum, Chenab, Ravi, Beas, Sutlej); flows into Arabian Sea; treaty (1960) — Indus Waters Treaty between India and Pakistan
- Ganga: Source: Gangotri (Gaumukh, Uttarakhand); Alaknanda + Bhagirathi = Ganga at Devprayag; major tributaries: Yamuna (Tons, Betwa, Ken, Son), Ghaghara, Gandak, Kosi; Ganga action plan launched (1985)
- Brahmaputra: Source: Mansarovar (Tibet); known as Yarlung Tsangpo in Tibet; enters India via Arunachal Pradesh as Dihang; major tributary: Subansiri; major flood-prone; Majuli island (Assam — world’s largest river island)
Peninsular Rivers
- West-flowing: Narmada (Marble Rocks at Bhedaghat; Sardar Sarovar Dam); Tapti (Surat); perennial; shorter courses
- East-flowing: Mahanadi (Chhattisgarh, Odisha — Hirakud Dam); Godavari (1,465 km, longest peninsular river; Dowleswaram Barrage); Krishna (Kolar, Telangana); Kaveri/Cauvery (Karnataka-Tamil Nadu — KRS Dam/Brindavan Gardens)
Climate Types (Koeppen Classification)
- Am: Tropical Monsoon (Western Ghats, Assam)
- Aw: Tropical Savanna (most of Peninsular India, plains of Odisha)
- BShw: Semi-Arid Steppe (Saurashtra, Kachchh)
- BWhw: Hot Desert (Rajasthan — Thar)
- Cwg: Humid Subtropical (North-East — Shillong)
- Dfc: Tundra/Cold Humid (Himalayan region — Ladakh, Sikkim)
- E: Polar Type (High Himalayas — not inhabited)
Environmental Issues
Air Pollution
- Delhi NCR: Severe; AQI >400 (very poor); stubble burning, vehicles, industries
- GRAP (Graded Response Action Plan): Stages I-IV based on AQI
- National Clean Air Programme (NCAP): 2019; 122 non-attainment cities
Water Pollution & Resources
- River pollution: Ganga (Kanpur, Varanasi), Yamuna (Delhi), Chambal (industrial effluents)
- Ganga River Basin Management Programme; Namami Gange Mission (2014)
- Groundwater depletion: Punjab, Haryana, Rajasthan; overexploitation for irrigation
- Fluorosis, arsenic contamination in West Bengal, Bihar
Biodiversity Threats
- Deforestation: 13.9 million hectares degraded forest land; shifting cultivation (NE India)
- Wildlife trafficking: Tigers, elephants, pangolins
- Invasive species: Water hyacinth (water bodies); Lantana camera (forests)
- Climate change impacts: Glacial retreat (Himalayan glaciers); cyclones intensifying; sea-level rise threatening coasts
Disaster Management
- Floods: Brahmaputra, Ganga, Mahanadi most affected; embankments failed in Bihar, Assam
- Earthquakes: Seismic zones I-V; Himalayan region (Zone V — highest risk); Gujarat (2001, Bhuj); Maharashtra (1993, Latur-Killari); Sikkim (2011); Nepal (2015 — affected Bihar, UP)
- Cyclones: Bay of Bengal more prone than Arabian Sea; Odisha (1999 — Paradip); Cyclone Amphan (2020, West Bengal-Bangladesh); Cyclone Tauktae (2021, Gujarat)
- Tsunami: December 2004 (Indian Ocean) — Andaman & Nicobar severely affected
🔴 Extended — Deep Study (3mo+)
Detailed — Himalayan System
The Himalayas form a crescentshaped barrier (2,400 km length, 150-400 km width) separating the Indian subcontinent from the Tibetan Plateau:
Geological Formation:
- Part of “Himalayas young fold mountains” — Tertiary period (5-7 crore years ago)
- Tethys Sea existed between Laurasia and Gondwanaland; sediments accumulated; continental collision (印 plate vs Eurasia plate) → Tethys sediments uplifted → Himalayas
- Still rising: 1 cm per year (approx.); susceptible to earthquakes (Sikkim 2011, Nepal 2015)
Three Sub-divisions of Himalayas:
| Range | Width | Altitude | Features |
|---|---|---|---|
| Himadri/Greater | 15-25 km | 6,000-8,000 m | Continuous; all peaks >7,600 m; glaciers (Siachen, Gangotri) |
| Himachal/Lesser | 80-100 km | 3,500-4,500 m | Valleys (Kashmir, Kangra); Pir Panjal, Dhauladhar |
| Shiwaliks/Sub | 10-50 km | 900-1,500 m | Youngest; unconsolidated sediments; Dun valleys |
Passes:
- Karakoram Pass (5,575 m); Nathu La (4,310 m — Sikkim-Tibet border, part of Silk Road); Zoji La (3,529 m — Kashmir); Banihal (2,832 m); Rohtang (3,978 m); Shipki La (3,970 m)
Western Ghats — Biodiversity Hotspot
Western Ghats extend from Tapi (Gujarat) to Kanyakumari (Tamil Nadu):
- 7 World Heritage Sites: Kalakad-Mundanthurai (Tamil Nadu), Silent Valley (Kerala), Agasthyamalai (Kerala), Periyar (Kerala), Eravikulam (Kerala), Anamalai (Tamil Nadu), Kudremukh (Karnationataka)
- Endemic species: Malabar Giant Squirrel, Lion-tailed Macaque, Nilgiri Tahr, Purple Frog (Myristica swamps)
- 325 threatened species; 50+ endemic fish; over 6,000 plant species (1,500 endemic)
Mineral Resources of Peninsular India
- Chota Nagpur Plateau: Mica (Koderma, Gaya — India’s largest), Coal (Jharia, Raniganj), Iron Ore (Singareni, Bailadila), Copper (Khetri, Singhbhum), Bauxite (Kalahandi, Sambalpur)
- Koderma: Mica city of India
- Dhanbad: Coal capital of India (Jharia coalfield)
- Jaduguda: Uranium mining (UCIL)
Agriculture & Soil Types
| Soil Type | Region | Features |
|---|---|---|
| Alluvial | Punjab, Haryana, UP, Bihar, Bengal | New (Khadar), Old (Bhangar); fertile, loamy |
| Black (Regur) | Deccan — Maharashtra, MP, Gujarat | Derived from Basalt; self-ploughing; moisture-retaining |
| Red | Tamil Nadu, Karnataka, Odisha | Crystalline rocks; iron oxide; less fertile |
| Yellow | Parts of Assam, Odisha | Less clay; loamy |
| Laterite | Karnataka, Kerala, Odisha, MP | Hard; acidic; humus poor; suitable for plantation |
| Desert | Rajasthan, Gujarat | Sandy; saline; low organic matter |
| Mountain | Himalayan region | Forest soils; high organic matter; acidic |
Soil Erosion & Conservation
- Water erosion: Sheet, rill, gully; 150 million hectares degraded
- Wind erosion: In arid regions (Thar)
- Conservation methods: Contour ploughing, terrace farming, bunding, strip cropping, afforestation, check dams, Ganga River cleaning (Namami Gange)
National Waterways & Irrigation
- National Waterway 1: Ganga-Bhagirathi-Hooghly (Haldia-Allahabad, 1,620 km)
- National Waterway 2: Brahmaputra (Dhubri-Sadiya, 891 km)
- National Waterway 3: West Coast Canal (Kottapuram-Kollam, 168 km)
- Major Dams: Hirakud (Mahanadi), Bhakra Nangal (Satluj), Sardar Sarovar (Narmada), Tungabhadra, Nagarjuna Sagar (Krishna), Mettur (Cauvery)
Common Mistakes to Avoid
- Confusing Western Ghats with Eastern Ghats characteristics
- Mixing up monsoon types — SW vs NE monsoons and their impacts
- Forgetting El Niño/La Niña effects on Indian monsoon
- Not knowing soil distribution — which soil where
- Confusing biosphere reserves with national parks — biosphere reserves include multiple zones (core, buffer, transition)
- Misidentifying source cities of major rivers (Gangotri vs Gaumukh)
Practice Tips
- Draw a relief map of India and label physical features, rivers, passes
- Memorize mountain peaks with heights, river lengths, rainfall data
- Practice matching wildlife species with their habitats
- Solve AILET GK on Indian Geography focusing on location-based questions
- Create flashcards for environmental issues with statistics
Exam Pattern Insights
- AILET GK has 5-8 questions from Geography & Environment
- Frequently asked: Rivers and their tributaries, passes, biosphere reserves (especially firsts and UNESCO sites), monsoon mechanism, soil types
- Source-based questions common — identify river, mountain, or state from given data
- Numerical data (heights, areas, rainfall amounts) frequently tested