CLAT– Geography

Universe & Solar System

• Universe = all celestial matter; study: Astronomy (bodies), Cosmology (origin)
• Big-Bang Theory: accepted origin model
• Galaxy types: Spiral, Elliptical, Irregular; Milky Way (spiral) ⇢ our solar neighbourhood
• Solar System: Sun + 8 planets, dwarf bodies, asteroids, comets
  • Inner planets: Mercury, Venus, Earth, Mars; outer: Jupiter, Saturn, Uranus, Neptune
  • Sun–Earth mean distance $1.5\times10^{8}\,\text{km}$ → light in $8.3\,\text{min}$
  • Key planet facts: Jupiter (largest), Mercury (smallest), Venus (brightest & hottest, Earth’s twin), Mars (red), Neptune (coldest & farthest)
  • Titan = only satellite with dense atmosphere

Earth: Shape, Motions & Position

• Shape: Geoid; measured by Geodesy
• Rotation: W→E; $23^{\circ}56'04''$ ≈ $24\,h$ → day/night
• Revolution: $365$ days along elliptical orbit; axial tilt $23.5^{\circ}$ causes seasons
• Key dates: Spring $21\,Mar$, Summer solstice $21\,Jun$, Autumn $23\,Sep$, Winter $22\,Dec$
• Perihelion $3\,Jan$ (nearest $147\,\text{M km}$); Aphelion $4\,Jul$ (farthest $152\,\text{M km}$)
• Moon: Perigee (nearest), Apogee (farthest); Solar eclipse (New Moon), Lunar eclipse (Full Moon)

Geographic Coordinates & Time

• Latitudes (0–$90^{\circ}$ N/S); important: Equator $0^{\circ}$, Tropics $23.5^{\circ}$, Polar circles $66.5^{\circ}$
• Longitudes $0–360^{\circ}$; Prime Meridian $0^{\circ}$, International Date Line $180^{\circ}$
• Crossing IDL: east → $-1$ day, west → $+1$ day
• Time zones: $15^{\circ}=1$ hour; IST $82.5^{\circ}E$ = GMT $+5:30$

Interior & Rocks

• Layers: Crust (Sial), Mantle (Sima), Core (Nife)
• Rock types: Igneous (granite), Sedimentary (sandstone), Metamorphic (marble)
• Crust composition: $\text{O}_2$ $46\%$ (max), Mg $1.5\%$ (min)

Atmosphere Essentials

• Major gases: $\text{N}<em>2$ $78\%$, $\text{O}</em>2$ $21\%$, Ar $0.93\%$, $\text{CO}_2$ $0.3\%$
• Layers (bottom→top): Troposphere (weather), Stratosphere (ozone), Mesosphere (coldest), Ionosphere (radio), Exosphere
• Greenhouse gases: Water vapour, $\text{CO}<em>2$, Methane, $\text{N}</em>2\text{O}$, Ozone

Natural Hazards

• Earthquake focus (hypocentre) & epicentre; magnitude: Richter $0–9$; study: Seismology
• Volcano types: Active, Dormant, Extinct; $68\%$ in Pacific Ring of Fire

Landforms & Continents

• 7 continents; Asia: largest; Africa: only one in all 4 hemispheres; Antarctica: “white continent”
• Major mountain ranges: Andes (longest), Himalaya (youngest; Everest $8848\,m$)
• Plateaus: Tibetan (highest, “roof of world”), Deccan (India)
• Deserts: Antarctica (largest cold), Sahara (largest hot)
• Grasslands names: Prairies (N-America), Pampas (S-America), Steppes (Eurasia), Savanna (Africa), Downs (Australia), Velds (S-Africa)

Hydrosphere & Water Bodies

• Water distribution: Oceans $97.25\%$, Ice $2.05\%$, Groundwater $0.68\%$
• Oceans: Pacific (largest/deepest), Atlantic (busy trade), Indian (only named after a country), Arctic (smallest/least saline)
• Deepest point: Mariana Trench (Pacific)
• Lakes: Baikal (deepest), Tanganyika (longest), Titicaca (highest navigable), Dead Sea (lowest)
• Important straits: Bering, Gibraltar, Malacca, Palk, Bab-el-Mandeb

Winds, Currents & Tides

• Planetary winds: Trade $0–30^{\circ}$, Westerlies $30–60^{\circ}$, Polar Easterlies $60–90^{\circ}$
• Ocean currents: clockwise N-hemisphere, anticlockwise S-hemisphere; e.g., Gulf Stream (warm), Oyashio (cold)
• Tides: Spring (Sun–Moon–Earth aligned, highest), Neap (right angle, lowest)
• Tropical cyclones naming: Hurricane (Atlantic), Typhoon (W-Pacific), Willy-Willy (Australia)

India: Size & Position

• Area rank: $7^{\text{th}}$; $2.42\%$ of world area
• Lat $8^{\circ}04'N$–$37^{\circ}06'N$; Long $68^{\circ}07'E$–$97^{\circ}25'E$
• Tropic of Cancer $23^{\circ}30'N$ passes 8 states; land boundary $\approx15\,200\,\text{km}$; coastline $7\,516.6\,\text{km}$
• Neighbours $7$: Bangladesh (longest $4097\,km$) > China > Pakistan > Nepal > Myanmar > Bhutan > Afghanistan
• Southernmost: Indira Point; northernmost: Indira Col

Major Physiographic Divisions (India)

1. Northern & N-Eastern Mountains (Himalaya + Purvanchal)
2. Northern Plains (alluvial; Bhabar → Terai → Bhangar → Khadar)
3. Peninsular Plateau (Central Highlands, Deccan; Ghats meet at Nilgiri)
4. Indian Desert (Thar; Luni river)
5. Coastal Plains (Western: Konkan–Malabar; Eastern: Northern Circars–Coromandel)
6. Islands: Andaman–Nicobar (10° Channel), Lakshadweep (9° & 8° Channels)

Drainage (India)

• Himalayan: Indus, Ganga, Brahmaputra systems
• Peninsular: Godavari (longest), Krishna, Mahanadi, Cauvery, Narmada & Tapti (west-flowing rift rivers)
• Largest delta: Sundarbans (Ganga-Brahmaputra)

Climate & Vegetation (India)

• Type: Tropical Monsoon; SW monsoon Jun–Sep (~$120$ days), NE monsoon Oct–Dec (Tamil Nadu)
• El Niño (warm Pacific) ↔ weak monsoon; La Niña ↔ heavy monsoon
• Forest types: Tropical Evergreen, Moist/Dry Deciduous (widest), Thorn, Montane, Mangrove (Sundarbans)
• Forest cover $24.56\%$ (2019); highest %: Mizoram; max gain: Karnataka

Soils & Agriculture

• Soil–crop links: Alluvial (rice, wheat), Black/Regur (cotton), Red (millets, pulses), Laterite (tea, coffee), Arid (barley)
• Crop seasons: Kharif (Jun–Oct), Rabi (Nov–Mar), Zaid (Apr–Jun)
• Green Revolution (post $1968$): HYV seeds, irrigation, fertilisers; Father in India: Norman Borlaug

Minerals & Energy (India)

• Coal: Jharkhand lead; Petroleum: Mumbai High, Assam, KG Basin; Natural Gas: western offshore, Assam
• Metallic: Iron (Odisha/Jharkhand), Manganese (Odisha), Bauxite (MP), Copper (MP)
• Power: Thermal $\approx65\%$, Hydel (Himalayan rivers), Nuclear (Tarapur, Kudankulam, Kalpakkam)

Transport Infrastructure

• Rail: 4th largest; longest route “Vivek Express” $4273\,km$; longest platform Gorakhpur $\approx1.3\,km$
• 13 major ports: Kandla, Mumbai, JNPT, Mormugao, Mangalore, Kochi, Paradip, Visakhapatnam, Chennai, Ennore, Tuticorin, Port Blair, Enayam (proposed)
• Major canals: Panama (Pacific–Caribbean), Suez (Mediterranean–Red), Kiel (Baltic–North)
• National Waterways: NW-1 (Allahabad–Haldia $1620\,km$) largest

Environment & Conservation

• Pollution types: Air, Water, Noise, Radioactive, Solid waste; key greenhouse gases: $\text{CO}<em>2$, $\text{CH}</em>4$
• Biodiversity hotspots in India: Western Ghats, Eastern Himalaya
• Protected areas: $18$ Biosphere Reserves (e.g., Nilgiri, Sundarbans), $166$ National Parks (1st: Jim Corbett), $515$ Wildlife Sanctuaries
• Flagship species: Tiger & Lion (only country with both)

Quick Superlatives

• Highest peak (world): Everest $8848\,m$; India: Kanchenjunga $8598\,m$
• Longest river (world): Nile $6690\,km$; India: Ganga $2525\,km$ within country length
• Largest lake (world): Caspian Sea; deepest: Baikal $1637\,m$
• Largest delta: Sundarbans $\sim10^{4}\,\text{km}^2$
• Largest plateau: Tibetan; largest desert: Antarctica; largest coral reef: Great Barrier (Australia)