The Himalayan ranges are not a single mountain wall but a layered geological-ecological complex with distinct hydrological roles. Examine with reference to the Greater, Lesser and Outer Himalaya.
Subtopic: Geography · Physical — Himalayan System
How to structure your answer
Introduction: The Himalaya runs 2,500 km from the Indus gorge in the west to the Brahmaputra bend in the east, formed by ongoing collision of the Indian and Eurasian plates since c. 50 million years ago.
Body — three dimensions: (1) Greater Himalaya (Himadri): 6,000+ metres, perpetually snow-clad, source of the great glaciers — Gangotri (29 km), Siachen, Zemu; feeds Indus, Ganga, Brahmaputra. (2) Lesser Himalaya (Himachal): 3,500–4,500 metres, Pir Panjal, Dhauladhar, Mahabharat ranges; hosts hill stations and lateral valleys (Kashmir, Kangra, Kullu); critical zone for landslides. (3) Outer Himalaya (Shivalik): 900–1,200 metres, Tertiary sedimentary, terai-bhabar belt and duns (Dehradun, Patli Dun); prone to flash floods and bhabar percolation. Trans-Himalayan ranges — Zanskar, Ladakh, Karakoram — lie north of the Greater Himalaya; the Karakoram has K2 (8,611 m) and Siachen.
Conclusion: The layered Himalaya operates as a single climatic, hydrological and ecological system — any one disturbance (e.g., Kedarnath floods 2013) reverberates through all three zones.
Written within the word limit
142 words · target 150 words · 9 min
Introduction: The Himalaya stretches 2,500 km from the Indus gorge in the west to the Brahmaputra bend in the east, raised by ongoing Indian-Eurasian collision since about 50 million years ago.
Body: The Greater Himalaya or Himadri, above 6,000 m and perpetually snow-clad, holds Gangotri (29 km, source of the Bhagirathi) and Siachen (about 70 km, longest non-polar glacier), feeding the Indus, Ganga and Brahmaputra. The Lesser Himalaya or Himachal (3,500–4,500 m) — Pir Panjal, Dhauladhar, Mahabharat ranges — carries hill stations and lateral valleys such as Kashmir, Kangra and Kullu, concentrating landslide and seismic risk. The Outer Himalaya or Shivalik (900–1,200 m) of Tertiary sediments hosts the terai-bhabar belt and duns like Dehradun and Patli Dun, prone to flash floods. The Trans-Himalayan Zanskar-Ladakh-Karakoram complex lies northward, containing K2 at 8,611 m.
Conclusion: Kedarnath 2013 confirmed that all three zones operate as a single hydrological system — any high-altitude shock cascades downstream within hours.
What an examiner expects to see
- Himalaya 2,500 km Indus to Brahmaputra
- Indian Plate–Eurasian Plate collision c. 50 Ma
- Greater Himalaya (Himadri) — Gangotri, Siachen glaciers
- Lesser Himalaya (Himachal) — Pir Panjal, Dhauladhar
- Outer Himalaya (Shivalik) — Tertiary, terai-bhabar
- Trans-Himalaya — Zanskar, Ladakh, Karakoram
- K2 (8,611 m) in Karakoram, 2nd highest
- Duns — Dehradun, Patli Dun, Kotli Dun
- Kedarnath flood 2013 — multi-zone disaster
Concrete cases, schemes and judgments
- Gangotri glacier — source of Bhagirathi
- Siachen glacier — 70 km, world's longest non-polar
- Pir Panjal as Kashmir Valley's southern wall
- Dehradun, Patli Dun as Shivalik valleys
- Karakoram Highway through Khunjerab Pass