Q. With reference to the Indus river system, of the following four rivers, three of them pour into one of them which joins the Indus directly. Among the following, which one is such river that joins the Indus directly? (UPSC Prelims 2021)
Answer: Sutlej
Notes: The correct answer is [D] Sutlej. This question refers to the specific geographical convergence of the "Panjnad" (five rivers) before they meet the Indus River in Pakistan.

• The Convergence Process: The Jhelum and Ravi rivers both flow into the Chenab. The Chenab then carries their combined waters and eventually meets the Sutlej at Panjnad, near Mithankot.
• Sutlej (Statement D – Correct): After receiving the combined flow of the other four rivers (Jhelum, Chenab, Ravi, and Beas), the Sutlej is the final collective stream that joins the Indus River directly.
• Chenab (Statement A – Incorrect): While the Chenab is the largest tributary of the Indus in terms of volume and receives the Jhelum and Ravi, it merges into the Sutlej at Panjnad before the final confluence with the Indus.
• Jhelum and Ravi (Statements B & C – Incorrect): These are secondary tributaries in this context. The Jhelum joins the Chenab at Trimmu, and the Ravi joins the Chenab further downstream. Neither reaches the Indus independently.

The Indus River system is governed by the Indus Waters Treaty (1960), which allocates the waters of the "Eastern Rivers" (Sutlej, Beas, Ravi) to India and the "Western Rivers" (Indus, Jhelum, Chenab) to Pakistan, subject to specific usage rights.