India: relief, rivers & drainage

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.

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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). Permalink · Report an error

Answer: (c) 3 only

The Rigvedic names of the Punjab rivers are Vitasta (Jhelum), Asikni (Chenab), Parushni (Ravi), Vipasa/Vipash (Beas) and Sutudri/Shutudri (Sutlej). Pairs 1 and 2 are swapped and the Beas was the Vipasa, so only Parushni-Ravi is right.

• ✗ 1. Vitasta is the Jhelum; the Chenab was called Asikni.
• ✗ 2. Asikni is the Chenab; the Jhelum was the Vitasta.
• ✓ 3. Parushni is the Rigvedic name of the Ravi.
• ✗ 4. The Beas was the Vipasa (Sanskrit Vipasha), not Yavyavati.

Remember · Rigvedic Punjab rivers: Vitasta–Jhelum, Asikni–Chenab, Parushni–Ravi, Vipash–Beas, Shutudri–Sutlej.

Question and answer: UPSC's provisional GS Paper I (2026, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink · Report an error

Answer: (c) Sutlej

The Sutlej (Satluj) rises near Mansarovar in Tibet, cuts across the Himalaya at Shipki La as an antecedent river, and feeds the Bhakra Nangal canals. It flows through China, India and Pakistan and ends as a tributary, merging into the Panjnad that joins the Indus, so it forms no delta or distributaries of its own.

• ✓ (c) All four clues fit: antecedent gorge across the Himalaya, three countries (China, India, Pakistan), a Tibetan source with major irrigation use, and a tributary that ends in another river rather than building distributaries.
• ✗ (b) The Indus is also antecedent and Tibetan, but it ends in a large delta on the Arabian Sea with several distributaries.
• ✗ (a) The Brahmaputra flows through China, India and Bangladesh but splits into many channels in the Ganga–Brahmaputra delta.

Remember · Satluj: rises at Rakas Tal near Mansarovar (Langchen Khambab), crosses Shipki La, antecedent; feeds Bhakra Nangal; joins the Indus via the Panjnad.

📘 Read it in NCERT: Class 11 India: Physical Environment, Ch 3 (practise this chapter) · Class 11 India: Physical Environment, Ch 3 (practise this chapter) · Class 11 India: Physical Environment, Ch 3 (practise this chapter)

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). Permalink · Report an error

Answer: (c) 2 and 3

UPSC's key treats statements 2 and 3 as wrong. West Bengal's border with Bangladesh alone is 2,216.7 km (plus borders with Nepal and Bhutan), and Sikkim is not alone in touching a single State: Meghalaya borders only Assam. Uttar Pradesh touches many States (and Delhi), more than any other State.

• ✓ 1. Uttar Pradesh borders many States and Delhi (Britannica lists Uttarakhand, Bihar, Jharkhand, Chhattisgarh, Madhya Pradesh, Rajasthan, Haryana and Delhi), more than any other State.
• ✗ 2. UPSC's official key treats this as incorrect. West Bengal's stretch of the India-Bangladesh border alone is 2,216.7 km; we could not confirm Rajasthan's own border length from an official source, so we do not state it.
• ✗ 3. Sikkim touches only West Bengal among Indian States, but Meghalaya likewise touches only Assam, so Sikkim is not the only such State.

Remember · Longest international border: West Bengal (Bangladesh 2,216.7 km + Nepal + Bhutan). Most neighbouring States: Uttar Pradesh. One-neighbour States: Sikkim (West Bengal), Meghalaya (Assam).

Question and answer: UPSC's provisional GS Paper I (2026, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink · Report an error

Answer: (b) 1 and 2

The Peninsular Block is an ancient, rigid landmass whose western edge has partly sunk beneath the sea and whose hills are old, worn-down remnants such as the Veliconda and Mahendragiri ranges. Its river valleys are shallow, so deep V-shaped valleys belong instead to the young Himalayan mountains.

• ✓ 1. NCERT describes the Peninsula as a rigid block since the Cambrian, except for part of its western coast that lies submerged beneath the sea, with other parts altered by tectonic activity.
• ✓ 2. The Peninsula mostly consists of relict and residual mountains, and NCERT lists the Veliconda hills and the Mahendragiri hills among them.
• ✗ 3. Peninsular river valleys are shallow with low gradients. Gorges and V-shaped valleys are marks of the young, fast-flowing rivers of the Himalayan mountains.

Remember · Peninsular Block: ancient rigid block, submerged western coast, relict and residual hills (Aravali, Nallamala, Veliconda, Mahendragiri), shallow valleys. V-shaped valleys are Himalayan.

📘 Read it in NCERT: Class 11 India: Physical Environment, Ch 2 (practise this chapter) · Class 11 India: Physical Environment, Ch 2 (practise this chapter) · Class 11 India: Physical Environment, Ch 2 (practise this chapter)

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). Permalink · Report an error