During the Indian monsoon season, the correct answer is option 2 - the easterly jet stream alone exists in the Indian region.

Jet streams are narrow, fast-moving air currents in the upper atmosphere. In the Indian region, there are two main jet streams known as the westerly and easterly jet streams.

The westerly jet stream exists during the winter months, bringing cold air from the western regions towards the Indian subcontinent. However, during the monsoon season, the westerly jet stream weakens and moves towards the north, causing it to no longer exist in the Indian region.

On the other hand, the easterly jet stream becomes dominant during the monsoon season. It brings warm and moist air from the Bay of Bengal and Arabian Sea towards the Indian subcontinent, resulting in heavy rainfall and the monsoon season.

Therefore, option 2 is correct as only the easterly jet stream exists in the Indian region during the monsoon season.

Alert - Correct answer should be option 3: during the Indian monsoon season, both westerly and easterly jet streams exist in the Indian region. The westerly jet stream weakens and moves towards the north, while the easterly