The correct option is Western Himalayas.
Explanation
The South-West Monsoon approaches the Indian subcontinent in two distinct branches due to the peninsular shape of the landmass: the Arabian Sea branch and the Bay of Bengal branch. The interaction and movement of these branches are governed by the low-pressure trough over the plains and the topography of the region.
Analysis of the Convergence:
- The Arabian Sea branch moves north-eastwards after crossing the Western Ghats and central India. A part of this branch moves parallel to the Aravallis and reaches Northwest India.
- The Bay of Bengal branch, after striking the Eastern Himalayas, is deflected to the west and moves up the Ganga plains. As it travels westward, it gradually loses moisture.
- These two branches eventually merge over the Northwestern part of the Ganga plains (including Delhi, Punjab, and Haryana) and the Western Himalayas.
- This convergence reinforces the moisture content in the atmosphere, leading to rainfall in the Western Himalayas and the adjacent plains.
Analysis of Incorrect Options:
- Northeastern States: These are primarily fed by the Bay of Bengal branch directly. The Arabian Sea branch does not reach here to reinforce it.
- Coromandel Coast: This region remains largely dry during the South-West Monsoon season because it lies in the rain shadow of the Western Ghats (for the Arabian Sea branch) and runs parallel to the Bay of Bengal branch. It receives the bulk of its rainfall from the North-East (Retreating) Monsoon.
- Deccan Plateau: This region receives rainfall from the Arabian Sea branch but lies in the rain shadow area of the Western Ghats. It is not the zone where the two branches converge.
Key Takeaway:
The Arabian Sea branch and the Bay of Bengal branch of the South-West Monsoon converge and reinforce each other over the Northwestern plains and the Western Himalayas.