RAS question
The southwest monsoon reaches India first at:
Correct answer: (C) Kerala coast (around 1 June).
The southwest monsoon first reaches India at the Kerala coast, normally around 1 June.
Explanation
The southwest monsoon's arrival in India is marked by its onset over Kerala, normally around 1 June. IMD's onset guidance treats this as a defined meteorological event, not just a day of local rain: rainfall at a required share of listed stations must align with supporting wind-field and outgoing longwave radiation conditions. After this onset, the monsoon advances northwards in surges. It follows two broad pathways: the Arabian Sea branch moves along the west coast through Kerala, Karnataka, Maharashtra, Gujarat and Rajasthan towards north-west India, while the Bay of Bengal branch enters through north-east India and turns westward along the Ganges plain. IMD also states that the monsoon usually covers the whole country around 15 July.
Why the other options are wrong
- (A) Mumbai is on the later west-coast advance of the Arabian Sea branch and receives the monsoon around 10 June, after Kerala.
- (B) Gujarat lies farther up the Arabian Sea branch's path and is reached only after the monsoon has already set in over Kerala and moved north.
- (D) Tamil Nadu is not the first point of southwest-monsoon onset; its rainfall is mainly associated with the north-east monsoon.
Concept
This tests the onset and advance of the Indian monsoon, a core physical geography idea. It recurs in RAS because it links seasonal winds, rainfall distribution and Rajasthan's later arrival of the Arabian Sea branch.