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:
Answer & explanation
Answer: (d) 3
River dolphins live only in fresh water and cannot pass from one river system to another through the sea. Finding the same kind of dolphin in both the Indus and the Ganga systems was therefore read as proof that the two systems were once joined, with a tributary such as the Yamuna or the Sutlej changing sides in the Pleistocene.
- ✗ 1. The Nadistuti (Nadi) Sukta is a hymn in praise of the rivers of north-west India. It names the rivers in order but says nothing about Pleistocene river courses.
- ✗ 2. Robert Bruce Foote is known for discovering Palaeolithic tools in South India (Pallavaram, 1863), not for exploring the Sutlej and the Yamuna.
- ✓ 3. A freshwater dolphin common to the Indus and the Ganga systems implies an old connection between them, which is exactly what the assertion claims. The Convention on Migratory Species document proposed by India treats the South Asian river dolphin, Platanista gangetica, as one species spread across rivers in India, Pakistan, Bangladesh and Nepal (the Indus form being a subspecies).
- • Since then The Indus and Ganges dolphins were long treated as one species; since 2021 scientists list them as two species, Platanista minor and Platanista gangetica (Britannica). The old argument used the single-species view.
Remember · The shared South Asian river dolphin of the Indus and Ganga systems is the classic clue that the two drainages were once linked through a shifting tributary.
📘 Read it in NCERT: Class 7 Exploring Society: India and Beyond (Part 1), Ch 8 (practise this chapter)
Sources
- NCERT Class 7 · Exploring Society: India and Beyond (Part 1), Chapter 8 “The nadistuti sukta of the Rigveda is a hymn (sukta) in praise of (stuti) rivers (nadi) that invokes 19 major rivers of ancient northwest India.”
- Convention on Migratory Species (UNEP/CMS), COP13 Concerted Action 13.6, South Asian River Dolphin (proposed by the Government of India) ↗ “The South Asian River Dolphin, Platanista gangetica spread across rivers in India, Pakistan, Bangladesh and Nepal.”
- Encyclopaedia Britannica, Ganges river dolphin ↗ · reference work “the Ganges river dolphin ( Platanista gangetica ) and the Indus river dolphin ( P. minor ), which are classified as endangered species”
Question and answer: UPSC's provisional GS Paper I (2026, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·