UPSC Prelims 2026 GS Paper I · Q25 of 98 Geography hard

Identify the river of the Indian sub-continent on the basis of the following information : 1. It has an antecedent drainage system. 2. It flows through three countries. 3. It originates in the Tibetan Plateau and is an important river for irrigation. 4. It does not form distributaries. Select the answer from the following :

  1. (a) Brahmaputra
  2. (b) Indus
  3. (c) Sutlej ✓ UPSC's answer
  4. (d) Teesta

Why the answer is (c)

• The Sutlej rises near Rakas Tal on the Tibetan Plateau, cuts through the Himalaya in the Shipki La gorge (antecedent drainage) and flows through China, India and Pakistan — three countries.

• It feeds the Bhakra-Nangal system and the Indira Gandhi Canal, making it central to irrigation in Punjab, Haryana and Rajasthan.

• Unlike the Indus and Brahmaputra it forms no delta or distributaries; it joins the Chenab to form the Panjnad, which meets the Indus.

• The Indus is excluded by clue 4 (it has a large delta with distributaries) and the Brahmaputra by clues 2 and 4; the Teesta rises in Sikkim, not Tibet, and flows through only India and Bangladesh.

• Hence option (c), Sutlej.

Why the other options are wrong

(a) Brahmaputra
The Brahmaputra forms distributaries in its delta and flows through China, India and Bangladesh but fails clue 4.
(b) Indus
The Indus forms a large delta with distributaries, contradicting clue 4.
(d) Teesta
The Teesta rises in Sikkim, not on the Tibetan Plateau, and crosses only two countries.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2026, held on 24 May 2026. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

Reading the answer is not the same as getting it right under a clock. Practise this question with UPSC's negative marking, and anything you miss goes into an error notebook until you get it right twice.

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