As a counter-measure to the devastating terrorist attack in Pahalgam which claimed 26 lives including 25 Indians and one Nepali national, India’s Cabinet Committee on Security announced on April 23, 2025, that “The Indus Waters Treaty (IWT) of 1960 between India and Pakistan will be held in abeyance with immediate effect, until Pakistan credibly and irrevocably abjures its support for cross-border terrorism.” While Pakistan has termed this suspension as an “act of war,” India’s position rests on solid legal foundations within international law, particularly given the doctrine of rebus sic stantibus (fundamental change of circumstances). This piece examines the legal validity of India’s decision and reaches the view that India’s denouncing the IWT aligns with established principles of international law.The Indus Waters Treaty, signed in 1960 under World Bank mediation, considered a rare success in India-Pakistan diplomacy, surviving multiple wars and persistent tensions, is more in favour of Pakistan.

The treaty divided the six rivers of the Indus system between the two nations: India received rights over the eastern rivers (Ravi, Beas, and Sutlej), while Pakistan gained control over the western rivers (Indus, Jhelum, and Chenab). In this arrangement, India received approximately 30 per cent of the total water carried by the rivers, while Pakistan received 70 per cent. The lopsided nature of the treaty is reflected as it allowed India limited use of western rivers for non-consumptive purposes such as power generation and irrigation under strict regulations, leaving the huge remainder in favour of Pakistan. Remarkably, the IWT has endured for over 65 years despite intermittent tensions between the two nations, a testament to its robust framework but more reflective of India’s resilience in not scrapping it for humanitarian considerations.

Numerous occasions arose in the past when India could have reconsidered the continuation of the treaty, however, it observed restraint perhaps in the hope of not undermining the prospects of friendliness with Pakistan in future.  Unilateral denunciation of IWT by India may be seen as an act of reprisal against the Pahalgam attack, but it is also a reflection of changing realities that now challenge its continued application in its current form. Though the IWT framework has no exit clause or specified duration, and conventionally, any modification of its terms would require consent from both parties, however, international law provides mechanisms for treaty suspension/termination under certain circumstances, which India has now invoked. India’s suspension of the IWT finds legal validity in the doctrine of rebus sic stantibus, codified in Article 62 of the Vienna Convention on the Law of Treaties (VCLT), 1969.

Although India is not a signatory to the VCLT, the principle is widely recognised as part of customary international law, making it applicable regardless of ratification status. Moreover, the VCLT does not provide all the circumstances under which a treaty could be suspended/terminated eg, aggression, fomenting civil strife and sponsoring terrorism in the territory of a treaty party, that could justify the validity of Indian stand under customary international law.   

Moreover, a fundamental change in circumstances can be invoked u/a 62 as ground for treaty termination or suspension when: “(a) the existence of those circumstances constituted an essential basis of the consent of the parties to be bound by the treaty; and (b) the effect of the change is radically to transform the extent of obligations still to be performed under the treaty”. Importantly, paragraph 3 of Article 62 explicitly mentions that a party may invoke fundamental change as grounds for “suspending the operation of the treaty”, which is precisely what India has done-not terminating the treaty but holding it in abeyance.

In addition, the doctrine of rebus sic stantibus provides an escape from the principle of pacta sunt servanda (agreements must be kept), embodied in Art 26 of the VCLT, which requires that “every treaty in force is binding upon the parties to it and must be performed by them in good faith”. The key element here is “good faith”  a condition that India argues Pakistan has violated through its continued support for cross-border terrorism, further justifying the Indian stand.

For invocation of rebus sic stantibus to be valid, it must be demonstrated that a fundamental change in circumstances has occurred since 1960 that was not foreseen by the parties, constituted an essential basis for consent to the treaty, and radically transforms the extent of obligations under the treaty. India’s stand on IWT satisfies these requirements on multiple grounds taken up hereinafter.

When the IWT was signed in 1960, the nature and scale of cross-border terrorism that India has faced over decades from Pakistan did not exist. The treaty was negotiated with the assumption of peaceful coexistence and mutual respect for sovereignty, however, the persistent support for terrorism directed against India fundamentally alters the context in which the treaty operates, violating the good faith principle that underlies all treaty obligations.

India’s suspension of the IWT is not a permanent termination but a conditional abeyance “until Pakistan credibly and irrevocably abjures its support for cross-border terrorism.” This formulation leaves room for the treaty’s revival under changed circumstances if Pakistan takes verifiable steps to address India’s security concerns. 

By framing the suspension as conditional rather than permanent, India has demonstrated restraint and left open pathways for resolution. India’s action may well establish an important precedent in international hydro-diplomacy as it sends a clear message that water-sharing agreements cannot be isolated from broader bilateral relations, especially when those relations are marred by security threats. The ball now rests in Pakistan’s court and by addressing India’s concerns regarding cross-border terrorism, Pakistan can create conditions for the treaty’s revival. Until then, India’s suspension stands as a legally defensible response to fundamentally changed circumstances in a volatile region.

(The writer is an Associate Professor at Faculty of Law, University of Delhi. Views expressed are personal)