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What does the Ganga Water Treaty with Bangladesh do, and what happens when it ends?

For thirty years one table in a treaty has decided how the Ganga's dry-season flow at Farakka is split between India and Bangladesh. The treaty's term ends in December 2026. Here is what it says, worked through, and what the official record says about what comes next.

Short answer

It shares the Ganga's flow at Farakka between India and Bangladesh in the dry months, 1 January to 31 May, by a formula: half each when 70,000 cusecs or less arrive, and above that a fixed 35,000 cusecs to Bangladesh or 40,000 to India, with the rest to the other. Signed on 12 December 1996 for thirty years, its term ends in December 2026. The latest official word found, a Lok Sabha answer of 1 August 2025, says talks on renewing it had yet to begin.

By 5 min read
Contents
  1. Why does Farakka matter?
  2. How does the treaty share the water?
  3. What if the river runs low?
  4. What happens when it ends?
  5. Why it matters for India
  6. Using this in the exam
Terms used in this essay
Cusec
One cubic foot of water flowing past a point every second: about 28.3 litres a second.
Lean season
The dry months, when the river carries least water. In the treaty, 1 January to 31 May.
Barrage
A low dam with gates across a river, used to raise the water level and divert part of the flow.
Feeder canal
The 38.38 km canal that takes water from the Farakka Barrage into the Bhagirathi.
Bhagirathi-Hooghly
The branch of the Ganga that flows south through West Bengal past Kolkata to the sea.
Annexure
A schedule attached to a treaty, part of it. Annexure I of this treaty holds the sharing formula.
Joint Rivers Commission
The India-Bangladesh body for shared rivers; its members head the committee that monitors the sharing.
The treaty in briefSigned in New Delhi on 12 December 1996 · covers 1 January to 31 May, in ten-day periods · valid for thirty years.

Every dry season, from January to May, India and Bangladesh share what the Ganga brings down to Farakka, in West Bengal, by a formula fixed in 1996. The treaty that holds it reaches the end of its thirty-year term in December 2026. Both questions in the title are answered by documents: the treaty's own text, and what India's government has told Parliament.

PSIR syllabusPaper II, India and South Asia: “Impediments to regional co-operation: river water disputes; illegal cross border migration; ethnic conflicts and insurgencies; border disputes.”

Why does Farakka matter?

Because it is where the Ganga's dry-season water can be divided. The Farakka Barrage, commissioned in 1975, stands on the Ganga in West Bengal, a short way above where the river enters Bangladesh. Its purpose, in the words of the Farakka Barrage Project, is to preserve and maintain Kolkata Port: a 38.38 km feeder canal, built to carry about 40,000 cusecs, takes Ganga water into the Bhagirathi-Hooghly, the branch that runs past Kolkata to the sea. What is not diverted flows on into Bangladesh.

Farakka, on the border with Bangladesh A map of India with West Bengal shaded and boxed, and dashed lines to a close-up of the state. In the close-up, the Farakka Barrage is marked in the north of the state, close to the border with Bangladesh, which lies to the east; Kolkata is marked in the south. The rivers are not drawn: below Farakka the Ganga flows on into Bangladesh, and a feeder canal takes part of its flow into the Bhagirathi-Hooghly, which runs south past Kolkata. India West Bengal Bangladesh FarakkaBarrage Kolkata Boundaries: Natural Earth, India view (simplified) Farakka, on the border with Bangladesh A map of India with West Bengal shaded and boxed, and dashed lines to a close-up of the state. In the close-up, the Farakka Barrage is marked in the north of the state, close to the border with Bangladesh, which lies to the east; Kolkata is marked in the south. The rivers are not drawn: below Farakka the Ganga flows on into Bangladesh, and a feeder canal takes part of its flow into the Bhagirathi-Hooghly, which runs south past Kolkata. India West Bengal Bangladesh FarakkaBarrage Kolkata Boundaries: Natural Earth, India view (simplified)
Farakka, near the border. The barrage stands in the north of West Bengal, just above where the Ganga flows into Bangladesh. The feeder canal sends part of its flow south down the Bhagirathi-Hooghly to Kolkata.

Before 1996 there were earlier arrangements: an agreement in 1977 and a memorandum of understanding in 1982. The 1996 treaty gave the sharing a thirty-year term.

How does the treaty share the water?

By a formula in Annexure I, applied in ten-day periods from 1 January to 31 May. Flow is measured in cusecs: one cubic foot of water passing every second, about 28.3 litres.

Annexure I: the sharing formula
Flow reaching FarakkaIndia's shareBangladesh's share
70,000 cusecs or less50%50%
70,000 to 75,000 cusecsthe balance35,000 cusecs
75,000 cusecs or more40,000 cusecsthe balance

Worked through: if 60,000 cusecs reach Farakka, each country gets 30,000. At 72,000, Bangladesh gets 35,000 and India the other 37,000. At 90,000, India gets 40,000 and Bangladesh the other 50,000. Below 70,000 the two shares are always equal; above 75,000 India's is capped at 40,000. That cap is the same figure the feeder canal was built to carry.

One condition sits under the table: between 1 March and 10 May, each country is guaranteed 35,000 cusecs in alternate three ten-day periods. A second annexure applies the formula to the average flows of 1949 to 1988, as an indicative schedule for each ten-day period.

How the treaty splits the flow at Farakka Line chart of each country's share against the flow reaching Farakka, from 40,000 to 100,000 cusecs, under Annexure I of the 1996 treaty. Up to 70,000 cusecs the two lines are one: half each. From 70,000 to 75,000, Bangladesh stays at 35,000 and India takes the rest, rising to 40,000. From 75,000 up, India stays at 40,000 and Bangladesh takes the rest, reaching 60,000 at a flow of 100,000. A dashed line at 50,000 marks the flow below which the treaty requires immediate consultations. India's share Bangladesh's share 0 20 40 60 40 50 60 70 80 90 100 flow reaching Farakka, thousand cusecs share, thousand cusecs below 50,000:consult at once India, flow 70,000 cusecs: 35,000 cusecs India, flow 75,000 cusecs: 40,000 cusecs India: 40,000 Bangladesh, flow 70,000 cusecs: 35,000 cusecs Bangladesh, flow 75,000 cusecs: 35,000 cusecs Bangladesh: the rest half each How the treaty splits the flow at Farakka Line chart of each country's share against the flow reaching Farakka, from 40,000 to 100,000 cusecs, under Annexure I of the 1996 treaty. Up to 70,000 cusecs the two lines are one: half each. From 70,000 to 75,000, Bangladesh stays at 35,000 and India takes the rest, rising to 40,000. From 75,000 up, India stays at 40,000 and Bangladesh takes the rest, reaching 60,000 at a flow of 100,000. A dashed line at 50,000 marks the flow below which the treaty requires immediate consultations. India's share Bangladesh's share 0 20 40 60 40 60 80 100 flow reaching Farakka, thousand cusecs share, thousand cusecs below 50,000:consult India, flow 70,000 cusecs: 35,000 cusecs India, flow 75,000 cusecs: 40,000 cusecs India Bangladesh, flow 70,000 cusecs: 35,000 cusecs Bangladesh, flow 75,000 cusecs: 35,000 cusecs Bangladesh half each
One formula, three regimes. Half each up to 70,000 cusecs; then Bangladesh's share is fixed while India's rises to 40,000; then India's is fixed and Bangladesh takes every extra cusec.

What if the river runs low?

Then the formula is not left to run on its own. If the flow at Farakka falls below 50,000 cusecs in any ten-day period, the two governments must enter into immediate consultations to make adjustments on an emergency basis (Article II). India may not reduce the water released to Bangladesh below Farakka, except for reasonable uses of up to 200 cusecs (Article III).

The treaty also provides for reviews, and for a floor while they run: if the two sides cannot agree on adjustments after a review, India is to release at least 90% of Bangladesh's share under the formula until they do (Article XI). A Joint Committee, headed by members of the Joint Rivers Commission from both countries, monitors the sharing.

The floorNo agreement after a review? India still releases at least 90% of Bangladesh's share (Article XI).

What happens when it ends?

That depends on the two governments, and the official record says little so far. The treaty is valid for thirty years from its signing on 12 December 1996, so its term runs to December 2026. Renewing it, or replacing it, needs both countries to agree.

The latest official statement this essay could find is a written answer in the Lok Sabha on 1 August 2025 by the Ministry of External Affairs. It said the treaty is set to expire in 2026 and that “bilateral discussions for its renewal are yet to commence”. Technical meetings on water continue under the Joint Rivers Commission, the last of them then in March 2025, and the Union government consults the Government of West Bengal, including at an inter-ministerial meeting on 26 March 2025. No later official statement on renewal was found when this essay was written, on 1 November 2026.

The formula governs the dry season only while the treaty is in force. Whether the lean season of 2027 is shared under a renewed treaty, a new one, or an interim arrangement is a question the official record has not yet answered, and this essay does not guess.

Why does it matter for India?

Two reasons sit in the documents above. Kolkata Port depends on the water the feeder canal carries, which is why the barrage was built; the treaty decides how much of the dry-season flow India may keep for it. And the river runs through a State: the Union government negotiates the treaty, but consults West Bengal on its renewal, as its answer to Parliament records.

Using this in PSIR and GS Paper II

Quote the formula's numbers and the dates. Try these:

  1. GS Paper II, 250 words. The Ganga Water Treaty of 1996 reaches the end of its term in December 2026. Explain its sharing formula and the questions its renewal must settle.
  2. PSIR, 15 marks. “River water disputes are an impediment to regional co-operation in South Asia.” Discuss with reference to the Ganga at Farakka.
  3. Prelims-style. Under the treaty, if 72,000 cusecs reach Farakka in a ten-day period, how much goes to Bangladesh? (35,000 cusecs.)

An outline for the first.

  1. Farakka and the feeder canal: why the dry-season flow must be divided.
  2. The formula (Annexure I), with one worked example, and the March to May guarantee.
  3. The safeguards: consultation below 50,000 cusecs (Article II), the 90% floor (Article XI), the Joint Committee.
  4. The term: thirty years from 12 December 1996; the official position as of August 2025.
  5. Close on what renewal must decide, without predicting it.

Practise: GS Paper II mock tests · Read: Geography (GS Paper I) · Exam: UPSC Civil Services

Sources

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