RAS question
Which is Rajasthan's longest east-flowing river?
Correct answer: (C) Banas.
Banas is Rajasthan's longest east-flowing river, running 512 km entirely within the state from the Khamnor Hills to its confluence with the Chambal near Sawai Madhopur.
Explanation
Banas is the right answer because the question is about Rajasthan's longest east-flowing river in the state context. It is 512 km long and is the longest river flowing entirely within Rajasthan. Rajasthan State Pollution Control Board records the route: Banas originates in the Khamnor Hills of the Aravali Range near Kumbhalgarh in Rajsamand district, flows through Rajasthan for its entire length, moves northeastwards through Mewar, and meets the Chambal near Rameshwar in Khandar Block of Sawai Madhopur district. That combination of length, all-Rajasthan course, and east/northeast drainage towards the Chambal makes Banas the correct choice.
Why the other options are wrong
- (A) Luni is not the answer because the question asks for an east-flowing river, while Luni flows west.
- (B) Chambal is not the answer because it is treated here as a north-flowing distractor, and Banas, not Chambal, flows for its entire length through Rajasthan.
- (D) Banganga is not the answer because it is shorter than Banas, so it cannot be Rajasthan's longest east-flowing river.
Concept
This tests Rajasthan drainage geography, especially direction of flow and river length within the state. RAS repeatedly asks such questions because river systems link physical geography with irrigation, settlement, and regional mapping.