Indian Monsoon

Correct answer: A. Because it creates favourable conditions for monsoon circulation over South Asia

Answer: A. The westerly jet stream is a fast-moving current of air in the upper atmosphere. Before the summer monsoon, the seasonal heating pattern over the Indian subcontinent changes the upper-air circulation. The westerly jet shifts north of the Himalayas, and this change is associated with the development of conditions that allow the summer monsoon circulation to establish over South Asia. A is correct because it states the connection without claiming that the jet alone causes every part of the monsoon. B is wrong because an upper-air wind shift does not turn seawater fresh. C is wrong because the shift does not remove all clouds; monsoon circulation generally involves widespread cloud formation and rainfall. D is wrong because the relevant seasonal change supports the summer monsoon, not a winter-only monsoon. Memory cue: upper-air circulation changes help open the way for summer monsoon conditions.

Correct answer: A. Because pressure, wind direction, humidity and cloudiness also change during withdrawal

The governing concept is that monsoon withdrawal is a gradual seasonal transition in the atmospheric circulation, not merely the end of rain at one place. As the monsoon retreats, pressure patterns, wind direction, moisture, humidity, cloud cover and rainfall activity can change. The timing and sequence may differ across regions, so a reduction in rainfall alone is not a complete diagnostic signal. Therefore option A is correct. Option B is false because withdrawal does not always produce floods across the whole country. Option C is false because withdrawal is observed over land as the rain-bearing circulation retreats. Option D is false because withdrawal is a recognised phase of the Indian monsoon cycle. The wider set of atmospheric indicators gives a more accurate understanding of the process.