Revision Sheet – Geography (Class 9)
=========================
Chapter 1: India – Size and Location
=========================
• India is one of the world's oldest civilizations.
• Latitudinal extent: 8°4′ N – 37°6′ N; Longitudinal extent: 68°7′ E – 97°25′ E.
• Tropic of Cancer (23°30′ N) passes through India.
• Area: 3.28 million sq. km (2.4% of world's land).
• Coastline: 7,516.6 km (including islands).
• N–S: ~3,200 km; E–W: ~2,900 km.
• Standard Meridian: 82°30′ E → IST.
• Neighbours: Pakistan, Afghanistan, China, Nepal, Bhutan, Bangladesh, Myanmar; by sea: Sri Lanka, Maldives.
• Political divisions: 28 States, 8 Union Territories.
• Connected with Europe & Africa via Indian Ocean; Suez Canal reduced distance by 7,000 km.
=========================
Chapter 2: Physical Features of India
=========================
India has 6 major physiographic divisions:
1. Himalayas – Youngest & highest (3 ranges: Himadri, Himachal, Shiwaliks).
2. Northern Plains – Formed by Indus, Ganga, Brahmaputra; fertile alluvium (Bhabar, Terai, Bhangar, Khadar).
3. Peninsular Plateau – Oldest landmass; Central Highlands & Deccan Plateau; mineral-rich.
4. Indian Desert – Thar Desert; <150 mm rainfall; Luni only river.
5. Coastal Plains – Western (Konkan, Kannad, Malabar); Eastern (Northern Circars, Coromandel); many deltas.
6. Islands – Andaman & Nicobar (volcanic), Lakshadweep (coral).
=========================
Chapter 3: Drainage (Rivers & Water Systems)
=========================
• Drainage: River system of an area.
• Two systems: Himalayan Rivers (perennial) & Peninsular Rivers (seasonal).
Himalayan Rivers:
- Indus: Origin Mansarovar; tributaries – Satluj, Beas, Ravi, Chenab, Jhelum.
- Ganga: Origin Gangotri Glacier (Bhagirathi); joins Alaknanda at Devprayag; tributaries – Yamuna, Ghaghara, Kosi, Son, Chambal; forms Sundarbans Delta.
- Brahmaputra: Origin Tibet (Tsangpo); enters Arunachal as Dihang; floods in Assam; joins Ganga Delta.
Peninsular Rivers:
- West-flowing: Narmada, Tapi (into Arabian Sea).
- East-flowing: Godavari, Mahanadi, Krishna, Kaveri (into Bay of Bengal).
Lakes:
- Freshwater – Bhimtal, Nainital, Wular (largest freshwater, J&K).
- Saltwater – Sambhar (Rajasthan), Chilika (Odisha).
Importance:
- Irrigation, hydropower, navigation, fisheries, drinking water.
- Pollution from industry & sewage → Namami Gange, NRCP.
=========================
Comparison Tables
=========================
Himalayan vs Peninsular Rivers
- Perennial (rain + glacier) | Seasonal (monsoon dependent)
- Long, deep valleys | Short, shallow valleys
- Large deltas | Small deltas/estuaries
- High water volume | Lower water volume
- Irrigation, transport | Hydropower, irrigation
Western Coast vs Eastern Coast
- Narrow, between Western Ghats & Arabian Sea | Wider, between Eastern Ghats & Bay of Bengal
- Divisions: Konkan, Kannad, Malabar | Divisions: Northern Circars, Coromandel
- Many estuaries, few deltas | Many deltas (Mahanadi, Godavari, Krishna, Kaveri)
- Ports: Mumbai, Mangalore, Kochi | Ports: Chennai, Vishakhapatnam, Paradip
Northern Plains (Alluvium types)
- Bhabar: Pebbles belt at foothills
- Terai: Marshy, wet, forested
- Bhangar: Older alluvium, terraces with 'kankar'
- Khadar: Newer alluvium, fertile, renewed yearly