With reference to the Himalayan rivers joining the Ganga downstream of Prayagraj from West to East, which one of the following sequences is correct?
Answer & explanation
Answer: (b) Gomati – Ghaghara – Gandak – Kosi
Follow the Ganga eastward from Prayagraj: the Gomati joins first at Kaithi (Ghazipur district, near Varanasi), then the Ghaghara near Chhapra, then the Gandak at Sonpur opposite Patna, and finally the Kosi further east in Bihar.
- ✓ (b) Gomati (Kaithi, Ghazipur) → Ghaghara (Chhapra) → Gandak (Sonpur, opposite Patna) → Kosi (eastern Bihar) is the west-to-east order of their confluences.
- ✗ (a) The Ghaghara cannot come first: the Gomati meets the Ganga upstream, near Varanasi, well before Chhapra.
- ✗ (d) The Kosi basin lies east of the Gandak and Burhi Gandak basins, so the Kosi joins after the Gandak, not before it.
Remember · Left-bank Himalayan tributaries of the Ganga, west to east: Ramganga, Gomati, Ghaghara, Gandak, Kosi, Mahananda.
📘 Read it in NCERT: Class 11 India: Physical Environment, Ch 3 (practise this chapter)
Sources
- NCERT Class 11 · India: Physical Environment, Chapter 3 “The important left bank tributaries are the Ramganga, the Gomati, the Ghaghara, the Gandak, the Kosi and the Mahananda.”
- Central Water Commission (Upper Ganga Basin Organisation): Gomti Basin ↗ “The river flows through an incised valley southwards through the districts of Sitapur, Lucknow, Barabanki, Sultanpur, and Jaunpur before meeting the Ganga river at Kaithi, District-Ghazipur, bordering Varanasi”
- India-WRIS Wiki: Gandak Basin ↗ “The Gandak Basin is bounded on north by the Himalayas. On the south by the River Ganga, On the east by the Burhi Gandak Basin and on the west by the Ghagra Basin.”
- India-WRIS Wiki: Kosi Basin ↗ “The Kosi basin is bounded on the north by the Himalayas, on the east by Mahananda basin, on the west by the Burhi Gandak basin and on the south by the river Ganga.”
Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·