UPSC Prelims 2012 Q88: Geography – Atmosphere & Climatology
Consider the following statements:
1. The duration of the monsoon decreases from southern India to northern India.
2. The amount of annual rainfall in the northern plains of India decreases from east to west.
Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (c) Both 1 and 2
Explanation
Monsoon duration and rainfall in India
| Statement | Verdict | Reason |
|---|---|---|
| 1. The duration of the monsoon decreases from southern India to northern India | Correct | The monsoon arrives first in Kerala (about 1 June) and leaves last from the south; the north-west gets it latest and loses it first |
| 2. The amount of annual rainfall in the northern plains of India decreases from east to west | Correct | The Bay of Bengal branch moves up the Ganga plain and loses moisture as it goes west |
Rainfall along the northern plains:
| City | Annual rainfall (about) |
|---|---|
| Kolkata | 160 cm |
| Patna | 110 cm |
| Prayagraj | 100 cm |
| Delhi | 65 cm |
Length of the rainy season: about four months in Kerala, but only about two months in western Rajasthan.
Answer: (c) Both 1 and 2.
Why each option is right or wrong
- (a) Incorrect. Statement 2 is also true; rainfall in the northern plains falls from east to west.
- (b) Incorrect. Statement 1 is also true; the duration of the monsoon shrinks northward.
- (c) CORRECT. Both the duration and the east-to-west fall in rainfall are true.
- (d) Incorrect. Both statements describe the Indian monsoon correctly.
Key point
Monsoon: onset in Kerala about 1 June, withdrawal from the north-west first; duration falls from south to north-west; rainfall in the Ganga plain falls from east (Kolkata) to west (Delhi).
Remember
Monsoon lasts longer in the south; plains get drier towards the west.
Common mistakes
- Thinking the monsoon lasts the same time all over India.
- Forgetting that the Bay of Bengal branch feeds the northern plains.
- Applying the plains pattern to the west coast, where the Western Ghats decide the rainfall.
Exam tip
First in, last out. The south gets the monsoon first and keeps it longest.
Sources
- NCERT Class XI — India: Physical Environment, Ch 4 (Climate)
- India Meteorological Department — Normal dates of onset and withdrawal of the south-west monsoon