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General Studies 2021 GS Paper I 15 marks 250 words Compulsory Explain

GS Paper I — Q14

Briefly mention the alignment of major mountain ranges of the world and explain their impact on local weather conditions, with…

Briefly mention the alignment of major mountain ranges of the world and explain their impact on local weather conditions, with examples. (Answer in 250 words) 15 marks

हिंदी में प्रश्न पढ़ें

विश्व की प्रमुख पर्वत श्रृंखलाओं के संरेखण का संक्षिप्त उल्लेख कीजिए तथा उनके स्थानीय मौसम पर पड़े प्रभावों का सोदाहरण वर्णन कीजिए । (250 शब्दों में उत्तर दीजिए)

Q14 of the 2021 UPSC Mains General Studies GS Paper I, as printed
The question as printed in the 2021 General Studies paper
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Model answer

Written by UPSC Answer Check against this question's marking rubric, to the 250-word length. UPSC does not publish answers for Mains — this is one way to score well, not an official key.

Mountain ranges are aligned by plate tectonics and orogeny, and their strike determines how they intercept prevailing winds. This is especially important where ranges cross prevailing wind belts. North–south ranges such as the Rockies and Andes block zonal westerlies. Moist air is forced to rise on the windward side, cools adiabatically, and gives orographic precipitation; descending air on the leeward side warms and dries, creating rain shadows. The Great Basin east of the Rockies and the dry Patagonian zone east of the Andes show this effect. East–west ranges such as the Himalayas and Alps act as broad climatic barriers and monsoon triggers. The Himalayas trap cold Siberian air in winter, enhance uplift of the southwesterly monsoon, and concentrate orographic rainfall along the foothills, Terai and sub-Himalayan belt, while the leeward Tibetan Plateau is drier; in India, this barrier helps maintain the monsoon by blocking northward flow. The Alps divide Mediterranean and continental air, producing foehn winds; cold-air drainage in valleys can create temperature inversions, fog and frost. Oblique alignments, not a uniform NW–SE trend, also intercept moisture: the Western Ghats, trending roughly N–S/NNW–SSE, block the Arabian Sea monsoon, giving heavy windward rain and a drier leeward Deccan, though not uniformly semi-arid; the Appalachians, trending NE–SW, moderate Atlantic moisture and local precipitation. Orographic lift cools air to saturation; descent warms it, producing dry, warm chinook/foehn winds, with chinooks warming the eastern Rocky slopes. Thus alignment shapes rainfall, temperature extremes and monsoon behaviour, making mountain strike a key determinant of local climate.

What "Explain" is asking you to do

Make the working of something clear — what sets it off, what follows from what, and what it produces. Explain is the Commission's mechanism word: it dominates the technical papers and the “explain why” stems, where the marks sit in the causal chain and not in the label.

Structure that answers it

State what it is → the initiating condition → the chain of cause, step by step → an instance where it plays out → what the chain produces

Where marks are lost

Describing what something looks like instead of why it works that way. Naming the stages without linking them reads as description too.

All UPSC directive words, compared →

How this answer will be evaluated

Approach

Framework: GS1 Geography: Physical Geography (Mountain Ranges & Climate). explain: definition/context > points in order > small example > short close Full marks: Clear alignment map + mechanism of rain shadow/orographic lift + specific examples.

Key points expected

  • Identify major ranges (Himalayas, Andes, Rockies, Alps)
  • Explain alignment (Circum-Pacific, Alpine-Himalayan belts)
  • Explain rain shadow effect mechanism
  • Explain orographic precipitation mechanism

Evaluation rubric

Each sub-part is marked on its own, against the marks and word limit printed on the paper.

  1. The answer Describe global mountain alignment and analyze their climatic impact with examples. 15 marks · 250 words

    explain— definition/context → points in order → small example → short close

    Must cover

    • Identify major ranges (Himalayas, Andes, Rockies, Alps)
    • Explain alignment (Circum-Pacific, Alpine-Himalayan belts)
    • Explain rain shadow effect mechanism
    • Explain orographic precipitation mechanism

    Loses marks

    • Listing ranges without explaining alignment
    • Describing weather without linking to mountains
    • Narrating chronology of mountain formation

    Earns more

    • Mention specific local weather changes (e.g., Gobi desert)
    • Reference jet stream deflection
    • Mention temperature lapse rate
    • Reference specific wind patterns (Westerlies/Monsoon)

    Extra mark

    • 30-second sketch map of global ranges
    • Specific statistic on rainfall difference (windward vs leeward)

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