RAS question
Which is the largest river basin in Rajasthan by area?
Correct answer: (C) Chambal basin.
The Chambal basin is the largest river basin in Rajasthan by area, covering about 21% of the state's geographical area.
Explanation
Rajasthan's largest river basin by area is the Chambal basin. The Government of Rajasthan's Ground Water Department drainage overview states that the Chambal catchment occupies 21% (72,032 sq. km) of the state's total geographical area. By catchment area within Rajasthan, Chambal outranks better-known or longer regional rivers. This basin includes the Banas, Kali Sindh and Parbati sub-basins, so Banas is counted within the wider Chambal system rather than as the largest basin on its own. A river basin's size depends on catchment area within Rajasthan, not only the river's name or regional familiarity.
Why the other options are wrong
- (A) Luni basin is large, but it is below the Chambal basin by area.
- (B) Banas is treated as a sub-basin within the wider Chambal system, so it is not the largest basin on its own.
- (D) Mahi basin is relatively small within Rajasthan, while the Government of Rajasthan's Ground Water Department drainage overview identifies the Chambal catchment as occupying 21% of the state's area.
Concept
Rajasthan drainage geography distinguishes a river name from its basin or catchment area. RAS often covers river systems, Aravalli drainage patterns and Rajasthan's regional physiography as standard map-based facts.