Karnataka signals intent to review Cauvery allocation citing Indus Waters Treaty

Why in news?

Karnataka told the Supreme Court it may seek reopening of Cauvery allocation, citing ‘changed circumstances’ and the Indus Waters Treaty example.

UPSC Relevance – Prelims: Article 262, Inter-State River Water Disputes Act, river tribunals, Cauvery basin, Indus Waters Treaty.

Mains, GS2: Issues and challenges pertaining to the federal structure; Disputes redressal mechanisms and institutions; Bilateral agreements involving India.

The issue in brief

• Tamil Nadu moved the Supreme Court complaining of a backlog in Cauvery water released by Karnataka.
• In reply, Karnataka argued the present allocation is inequitable and that circumstances have changed. It reserved its right to seek reopening of the Tribunal award read with the 2018 Supreme Court judgment.
• It relied on the Doctrine of Rebus Sic Stantibus and pointed out that India itself is seeking modification of the 1960 Indus Waters Treaty on the same ground.

Cauvery dispute 

• The Cauvery rises at Talakaveri in the Brahmagiri hills (Kodagu, Karnataka) and flows through Karnataka and Tamil Nadu into the Bay of Bengal. Kerala and Puducherry are also basin States.
• The dispute goes back to the 1892 and 1924 agreements between the Madras Presidency and the princely State of Mysore. Karnataka has long argued these were unfair to it.
• To resolve the dispute, Cauvery Water Disputes Tribunal (CWDT) was set up in 1990. It gave an interim order in 1991 and its final award in 2007, notified in 2013.
• State of Karnataka vs State of Tamil Nadu (2018): The Supreme Court modified the award, declared inter-State rivers a national asset, gave highest priority to drinking water (Bengaluru’s needs), and said the arrangement would hold for 15 years.
• On the Court’s direction, the Centre set up the Cauvery Water Management Authority (CWMA) and the Cauvery Water Regulation Committee (CWRC) in 2018. 

Constitutional and legal framework

• Entry 17, State List: Water (supply, irrigation, canals, drainage, storage, hydropower) is a State subject, but it is subject to Entry 56 of the Union List.
• Entry 56, Union List: Parliament can regulate and develop inter-State rivers in public interest. The River Boards Act, 1956 was made under it, though no river board has ever been set up.
• Article 262: Parliament may provide for adjudication of inter-State water disputes and may bar the Supreme Court and other courts from hearing them.
• Inter-State River Water Disputes (ISRWD) Act, 1956: The Centre sets up a tribunal on a State’s request if negotiation fails. Section 11 bars court jurisdiction over the dispute itself.
• 2002 Amendment: Tribunal to be set up within one year of request; award within three years (extendable by two). The award has the same force as a Supreme Court order or decree.
• Role of the Supreme Court: Despite Section 11, the Court held in 2018 that it can hear appeals against tribunal awards under Article 136. So, in practice, disputes return to the Court.

Rebus sic stantibus: can it apply between States?

• The Latin phrase means ‘things standing thus’. It allows a party to end or revisit a treaty when there is a fundamental change of circumstances that the parties did not foresee.
• It is codified in Article 62 of the Vienna Convention on the Law of Treaties, 1969. It is applied very narrowly. In the Gabčíkovo–Nagymaros case (1997), the ICJ rejected Hungary’s plea based on it.
• India and the IWT: India sent notices to Pakistan in January 2023 and September 2024 seeking modification of the treaty, citing population growth, clean energy needs and cross-border terrorism. After the Pahalgam attack, India put the treaty in abeyance in April 2025.
• Why the comparison is weak: The IWT is a treaty between sovereign nations under international law. The Cauvery allocation is a tribunal award with the force of a Supreme Court decree, binding under the Constitution. Domestic federal obligations cannot be dropped the way a sovereign may question a treaty.
• Where is it justified : Fixed allocations do not adjust well to climate variability, urban growth and changing cropping patterns. Global practice, such as the Helsinki Rules (1966) and the UN Watercourses Convention (1997), favours equitable and reasonable utilisation, which needs periodic review.

Way forward

• Make CWMA stronger and more technical: Real-time telemetry of inflows and releases, published openly, to reduce disputes over facts.
• A clear distress-sharing formula: Based on actual inflows, crop stage and drinking water needs, worked out in advance rather than during a crisis.
• Revive the 2019 reform: A permanent tribunal with fixed timelines and a strong negotiation stage before adjudication.
• Basin-level planning: River basin organisations as suggested by the Mihir Shah Committee (2016) and the draft River Basin Management Bill.
• Demand management: Micro-irrigation, less water-intensive crops in the delta, wastewater reuse and lake revival in Bengaluru.
• Cooperative federalism: Using the Inter-State Council and Zonal Councils for dialogue, so that water is seen as a shared national asset and not a zero-sum game.

Periodic review of allocations is reasonable in a changing climate. But it must happen through agreed institutions and data, not by unilateral reopening of settled awards. Otherwise every dry year will reopen old wounds.

Indus Water Treaty 

• Signed: At Karachi on 19 September 1960, with retrospective effect from 1 April 1960. The signatories were Nehru and Ayub Khan, after about nine years of talks brokered by the World Bank. The Bank also signed for certain provisions.  
• Eastern rivers (Ravi, Beas, Sutlej): Allotted to India, with an average annual flow of about 33 million acre-feet (MAF).  
• Western rivers (Indus, Jhelum, Chenab): Allotted mainly to Pakistan, about 135 MAF. In effect, Pakistan gets about 80% of the system’s water.
• India’s rights on western rivers: Domestic use, non-consumptive use, limited irrigation, and run-of-river hydropower designed to Annexure D criteria. Total storage is capped at about 3.6 MAF.
• Permanent Indus Commission (PIC): One commissioner from each country. It shares data, conducts inspections and meets every year. The last meeting (the 118th) was in May 2022.
• Dispute resolution (Article IX), graded in three tiers:
  • Question: Handled by the PIC.
  • Difference: A technical matter that goes to a Neutral Expert (NE) appointed by the World Bank under Annexure F.
  • Dispute: A legal matter that goes to a seven-member Court of Arbitration (CoA) under Annexure G.
• The treaty can be modified only by a new, ratified treaty (Article XII(3)) and terminated only by mutual agreement (Article XII(4)). It contains no exit clause.
• Present status 
  • 31 August 2026 award: A five-member Court of Arbitration unanimously declared the treaty fully in force and India still bound by it. It also imposed limited interim restrictions on some concreting work at Ratle until shortly after the Neutral Expert’s final decision.  
  • India’s response: India rejected the award and maintains the treaty is still in abeyance. India continues to take part in the Neutral Expert process while refusing to recognise the Court of Arbitration. Government sources said in July 2026 that the treaty would have to be reviewed and renegotiated before its water-sharing provisions could work again in any form. 

Practice MCQ 

Q1. Consider the following pairs:

Water Disputes Tribunal : States involved

1. Vansadhara : Odisha and Andhra Pradesh
2. Mahadayi : Goa, Karnataka and Maharashtra
3. Mahanadi : Odisha and Chhattisgarh
4. Krishna (KWDT-II) : Karnataka, Maharashtra and Tamil Nadu

How many of the pairs given above are correctly matched?

(a) Only one

(b) Only two

(c) Only three

(d) All four

Answer: (c)

Explanation: Pair 4 is incorrect as Tamil Nadu is not a party to the Krishna dispute; the States are Maharashtra, Karnataka, Andhra Pradesh and Telangana.

Q2. Consider the following statements:

Statement-I: The Supreme Court cannot hear appeals against the award of a water disputes tribunal constituted under the Inter-State River Water Disputes Act, 1956.

Statement-II: Article 262 of the Constitution allows Parliament to exclude the jurisdiction of the Supreme Court over inter-State water disputes.

Which one of the following is correct in respect of the above statements?

(a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I

(b) Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I

(c) Statement-I is correct, but Statement-II is incorrect

(d) Statement-I is incorrect, but Statement-II is correct

Answer: (d)

Explanation: In the Cauvery judgment (2018), the Supreme Court held that it can hear appeals against tribunal awards under Article 136. Section 11 of the ISRWD Act bars courts from the original dispute, not from appeals against the award.

Mains Practice Question 

“Inter-State river water disputes in India are less about water and more about weak institutions and trust deficit among States.” Examine in the context of the Cauvery dispute and suggest reforms to the dispute resolution mechanism. (15 marks, 250 words)

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