RAS question
The Narmada and Tapti rivers are unique among peninsular rivers because they:
Correct answer: (D) Flow westward into the Arabian Sea through rift valleys.
The Narmada and Tapti rivers are unique among major peninsular rivers because they flow westward into the Arabian Sea through fault or rift valleys.
Explanation
Most major rivers of southern or peninsular India flow east because the peninsular block has a general eastward tilt. NIOS marks Narmada and Tapi as the key exceptions: both flow through fault or rift valleys. That is why option D is the substantive answer, not merely a direction of flow. These rivers occupy fault-bounded depressions rather than ordinary self-cut river valleys. Narmada, 1312 km long, runs between the Vindhya and Satpura ranges and reaches the Arabian Sea; Tapti, about 724 km long, also runs westward from central India. Their narrow, steep-sided valley setting helps explain why they form estuaries rather than large deltas.
Why the other options are wrong
- (A) Narmada and Tapti are independent west-flowing rivers, not northward tributaries of the Ganga system.
- (B) They originate in central India, whereas the Eastern Ghats are associated with the eastern side of the peninsula.
- (C) They are not India's longest rivers; the Ganga and Godavari are longer.
Concept
This tests the drainage pattern of peninsular India, especially the exception created by rift-valley west-flowing rivers. RAS repeats this idea because it links physical geography, relief structure and river morphology in one factual frame.