UPSC Mains 2021 GS Paper 1 Q4: model answer
Differentiate the causes of landslides in the Himalayan region and Western Ghats.
What the question wants
Compare the causes of landslides in the Himalaya and in the Western Ghats.
How to structure it
Differentiate: a side-by-side comparison. A table works well.
- Geology
- Trigger
- Type of slide
- Human factors
- Common ground
How to think it through
This is the 2013 question again, now at 150 words. The Ghats half is now richer: Kerala 2018 and Wayanad 2024. Use the table to show you see two different machines producing the same result.
Model answer
The NRSC Landslide Atlas (2023) shows the Himalaya and the Western Ghats together account for most of India's landslides, but for different reasons.
Himalaya
- Geology: young, rising fold mountains; fractured and weathered rock; thrust faults (MCT, MBT).
- Trigger: earthquakes, cloudbursts, glacial melt and freeze–thaw, often several at once.
- Type: rock falls, debris flows and deep-seated slides, often along river gorges.
- Human factors: roads, tunnels, hydropower and tourist towns (Joshimath).
Western Ghats
- Geology: old, stable basalt and granite, but with a thick layer of weathered laterite soil on steep slopes.
- Trigger: intense, prolonged monsoon rain saturating the soil; low seismic role.
- Type: shallow soil slides and debris flows ('urul pottal' in Kerala).
- Human factors: quarrying, plantations replacing forests, construction on slopes (Kerala 2018; Wayanad 2024).
Common ground
Both need hazard zonation, slope drainage, limits on quarrying and construction, and early warning. The Gadgil report (2011) on ecologically sensitive zones remains relevant. The Himalaya needs engineering and seismic codes; the Ghats need forest cover and quarry controls above all.
Draw: Comparison table: geology, trigger, type, human cause.
Keywords, cases and data to drop in
thrust faults, laterite cap, soil piping, Wayanad 2024, Gadgil and Kasturirangan reports, Landslide Atlas.
Where most answers lose marks
- Repeating Himalayan causes for both regions.
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Question text as printed in the official UPSC Civil Services (Main) question paper. The model answer is original Battle IAS work; use it to learn structure, not to memorise.
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