UPSC Prelims 2002 Q3: Geography – Indian Physical Geography
- (a) About one - third of the area of the country records more than 750 millimetres of annual rainfall
- (b) The dominant source of irrigation in the country is wells
- (c) Alluvial soil is the predominant type of soil in the northern plains of the country
- (d) The mountain areas account for about thirty percent of the surface area of the country
Answer: (c) Alluvial soil is the predominant type of soil in the northern plains of the country
Explanation
Facts about India's rainfall, irrigation, soils and mountains
| Statement | Verdict |
|---|---|
| One-third of the area gets more than 750 mm annual rainfall | Wrong — roughly two-thirds of the country receives more than 750 mm |
| Wells are the dominant source of irrigation | Arguable — wells and tube wells now supply the largest share, but the official key does not choose this |
| Alluvial soil predominates in the northern plains | Correct — the Indo-Gangetic-Brahmaputra plains are built of alluvium |
| Mountain areas account for about thirty percent of the surface | Loose figure — hills and mountains are often put near 30 per cent, but it is not the key |
Alluvial soil covers about 40 per cent of India and is the predominant soil of the northern plains, carried down by the Indus, Ganga and Brahmaputra systems. This is the statement the official key accepts. Note for honesty: statement (b) about wells is also close to modern data, so the circulated key reflects the examiner's intended single answer.
Answer: (c) Alluvial soil is the predominant type of soil in the northern plains of the country.
Why each option is right or wrong
- (a) Incorrect. More than 750 mm falls over about two-thirds of the area, not one-third.
- (b) Incorrect. The official key rejects it, although wells and tube wells are in fact a leading irrigation source today.
- (c) CORRECT. The northern plains are predominantly alluvial.
- (d) Incorrect. The official key rejects it; the 30 per cent figure is only an approximate figure.
Key point
Alluvial soil: about 40% of India, found in the northern plains and east coast deltas; rich in potash, poor in phosphorus.
Remember
Alluvial soil is the main soil of the northern plains.
Common mistakes
- Choosing wells because they are a major irrigation source in the north.
- Underestimating the area receiving above 750 mm rainfall.
- Not noticing that the soil statement is the one that is unambiguous.
Exam tip
In a 'which is correct' question, pick the statement with the least ambiguity, here alluvial soil.
Sources
- NCERT Class XI — India: Physical Environment (Soils)
- Ministry of Agriculture — land use statistics