QUESTION

Hard

Physical Geography

Prelims 2026

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 ?

The Nadi-Sukta of the Rigveda
The explorations of the Sutlej and the Yamuna by Robert Bruce Foote
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 :

Select an option to attempt

Explanation

Statement 1 is Incorrect: The Nadi-Sukta of the Rigveda (Rigveda 10.75) lists rivers like the Ganga, Yamuna, Sarasvati, and Sutlej from east to west. It reflects Holocene (historical/human) geography, not Pleistocene geological shifts, which occurred long before the Vedic period.

Statement 2 is Incorrect: Robert Bruce Foote is known as the "Father of Indian Prehistory" for discovering India's first Paleolithic handaxe at Pallavaram (Tamil Nadu) in 1863. His explorations focused on stone-age archaeology in South India and Gujarat, not the geological mapping of the Sutlej and Yamuna river shifts.

Statement 3 is Correct: The presence of closely related blind river dolphins (Platanista gangetica minor in the Indus and Platanista gangetica gangetica in the Ganga) in two completely separated basins is a primary biological basis for asserting that these river systems were once physically connected. Geologists propose that during the Pleistocene epoch, a single massive river (the Indo-Brahma or Shiwalik river) connected the modern Indus and Ganga basins. Tectonic uplift (such as the Delhi Ridge) later separated them into distinct drainage systems, causing river avulsion (shifting) where the Yamuna shifted east to join the Ganga and the Sutlej shifted west to join the Indus.

Therefore, the correct option is D.

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