UPSC Prelims 2026 Question:

Consider the following assertion:

In the Pleistocene period either the Yamuna once flowed into the Indus, or the Sutlej flowed into the Yamuna and one major tributary of either had shifted from the Ganga to the Indus or vice versa.

Which of the following is/are the basis of the above assertion?

1. The Nadi-Sukta of the Rigveda
2. The explorations of the Sutlej and the Yamuna by Robert Bruce Foote
3. The presence of the same species of dolphins in both the Indus and the Ganga river systems

Select the answer using the code given below:

Explanation:

● The Nadi-Sukta of the Rigveda provides literary references to rivers of ancient India, but it is not considered scientific evidence for river capture or paleochannel shifts during the Pleistocene period. So, statement 1 is not correct.

● Robert Bruce Foote made important contributions to Indian geology and prehistory, the given assertion is not specifically based on his explorations of the Sutlej and Yamuna rivers. So, statement 2 is not correct.

● The presence of the same species of river dolphins in both the Indus and Ganga systems suggests that these river systems were once interconnected. So, statement 3 is correct.

Therefore, option (4) is the correct answer.