UPSC Prelims 2015 Q66: Geography – Atmosphere & Climatology
Consider the following statements:
1. The winds which blow between 30° N and 60° S latitudes throughout the year are known as
westerlies.
2. The moist air masses that cause winter rains in North - Western region of India are part of
westerlies.
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (b) 2 only
Explanation
Westerlies and winter rain in North-West India
| Statement | Verdict | Fact |
|---|---|---|
| 1. The winds which blow between 30° N and 60° S latitudes throughout the year are known as westerlies | Incorrect | Westerlies blow between 30° and 60° in each hemisphere, not from 30° N to 60° S |
| 2. The moist air masses that cause winter rains in North-Western region of India are part of westerlies | Correct | Western disturbances come from the Mediterranean with the westerly jet stream |
Planetary winds:
| Wind | Latitudes | Direction |
|---|---|---|
| Trade winds | 30° to the Equator | From the east |
| Westerlies | 30° to 60° | From the west |
| Polar easterlies | 60° to the Poles | From the east |
Winter rain from western disturbances helps the rabi wheat crop of Punjab and Haryana.
Answer: (b) 2 only.
Why each option is right or wrong
- (a) Incorrect. Statement 1 mixes hemispheres: 30° N to 60° S is not the westerly belt.
- (b) CORRECT. Winter rains in North-West India come with the westerlies.
- (c) Incorrect. Statement 1 is false because of the wrong latitudes.
- (d) Incorrect. Statement 2 is true; western disturbances ride the westerlies.
Key point
Westerlies: 30° to 60° in both hemispheres. Western disturbances from the Mediterranean bring winter rain to North-West India, good for rabi wheat.
Remember
Westerlies = 30° to 60° in each hemisphere.
Common mistakes
- Not spotting the trick: 30° N to 60° S crosses the Equator.
- Linking winter rain in Punjab to the retreating monsoon.
- Forgetting the Mediterranean origin of western disturbances.
Exam tip
Read latitude statements letter by letter. N and S were swapped to set the trap.
Sources
- NCERT Class XI — Fundamentals of Physical Geography, Ch 10 (Atmospheric Circulation and Weather Systems)
- NCERT Class XI — India: Physical Environment, Ch 4 (Climate)