India and Pakistan tension escalates with suspension of historic water treaty

India has taken the highly significant step of suspending the 1960 Indus waters treaty, which governs water sharing with Pakistan, as part of its response to the April 22 terrorist attack in Kashmir that killed at least 26 people.

India’s foreign secretary, Vikram Misri, said that “the Indus Waters Treaty of 1960 will be held in abeyance with immediate effect, until Pakistan credibly and irrevocably abjures its support for cross-border terrorism”.

India holds Pakistan responsible for the attack, and has responded by putting in place several other measures including telling Pakistani nationals to leave the country.

The attack happened in Pahalgam in the part of Kashmir controlled by India. Both India and Pakistan claim the region, which has been the site of several military conflicts since 1947 and a long-running insurgency since the 1990s.

The thorny question of shared rivers — a legacy of the partition of India and Pakistan at independence from British rule in 1947 — is now entangled with the larger, and escalating, dispute between the counties.

A formal letter from India’s water resources ministry cited both “sustained cross border terrorism by Pakistan” and Pakistan’s refusal to renegotiate the terms of the treaty as key reasons for its suspension.

The treaty suspension could harm Pakistani agriculture in the short term, and seriously disrupt downstream irrigation water supplies to farmers. Significantly, the decision abruptly changes the treaty’s status from an agreement that has been largely (if not fully) insulated from the decades-long conflict between India and Pakistan.

The 1960 treaty splits the management of the transnational Indus River basin between the two countries. India gained full rights over the Ravi, Beas and Sutlej, three tributaries of the Indus River known collectively as the eastern rivers. Pakistan gained most of the rights over three western rivers – the Indus main stem and two more tributaries, the Jhelum and Chenab.

Depoliticising water, and building towards peace in Kashmir, were two starting points for the eight years of World Bank-sponsored negotiations that produced the treaty. The treaty’s success has been to make water sharing a bureaucratic process and reducing the political heat.

More recently, growing disagreement has stemmed from India’s right to build some hydropower plants on the western rivers. Pakistan has objected to Indian project designs, arguing that they breach the terms of the treaty. India has accused Pakistan of intransigence in blocking its projects.

Since 2023, when India demanded amendments to the treaty, the two countries have held inconclusive talks. The suspension of the treaty is a new move, but also a logical development of increasing bilateral tensions over the treaty, which was kept separate from security issues for decades.

Indian politicians threatened to reduce water supplies to Pakistan in response to terrorist attacks in 2016 and 2019. The threat to punish Pakistan is likely to play well in India while public shock and anger over the attack is fresh. It also distracts attention from questions about possible Indian intelligence failures.

But previous threats stopped short of putting the Indus waters treaty into abeyance, so the suspension now needs to be taken seriously.

The impact will vary depending on how long it lasts. With the treaty suspended, India could change the way it operates existing water-control infrastructure on the western rivers.

Its engineers could flush sediment out of the reservoir of the upstream Kishenganga hydroelectric project and then refill the reservoir over a period of days. Previously, under the treaty, this could only be done during the peak monsoon period when water levels are highest.

It could now happen earlier, refilling reservoirs just when downstream farmers in Pakistan, who depend heavily on river water for irrigation, need a plentiful supply at the beginning of the crop-sowing season. India could also stop sharing water-flow data with Pakistan, making it harder for the latter to plan the management of its own hydropower and flood-control infrastructure.

Longer term, India could construct bigger projects on the western rivers that do not need to comply with the Indus waters treaty’s restrictions, more seriously reducing water availability in Pakistan. It would take years, though, for India to build these projects.

What does India hope to gain?

India stands to gain from using the treaty as leverage. The demand that Pakistan “abjure its support for cross-border terrorism” holds the resumption of water cooperation hostage to progress on a wider point of bilateral conflict, and strengthens India’s hand in renegotiating the treaty.

Internationally, treaty suspension may seem a comparatively measured response by India. Other forms of signalling displeasure, such as nuclear posturing, are too reputationally risky for a country that has worked hard to project itself as a responsible nuclear-armed state.

But Indian leaders will be aware that stopping the flow of the Indus waters is a potential red line for Pakistan and that Indian decisions about water sharing could goad Pakistan into nuclear threats.

India’s decision to suspend the water treaty has already predictably pushed Pakistan to make a subtle nuclear threat on April 24. It suggested that blocking or diverting water allocated to Pakistan under the treaty would be an “act of war,” and that it would consider the “complete spectrum of national power” as a response.

An escalation of rhetoric has already ensued between the two countries, with Pakistan announcing that it would “exercise the right to hold all bilateral agreements with India… in abeyance”, including the Simla agreement that ended the 1971 war between India and Pakistan.

Fears of escalation

There are fears that the current crisis could follow the path of the dangerous escalation seen in 2019, when Indian prime minister, Narendra Modi, authorised an airstrike on Pakistani soil following a terror attack that killed dozens of Indian security personnel. Pakistan responded with airstrikes on Indian-administered Kashmir before both sides found a way to deescalate the situation.

Today, the US, a traditional mediator between these two nations at crisis moments, may play a hands-off role. However, new facilitators such as China, Saudi Arabia and the UAE seemingly played a part in winding down tensions in 2019, and could step in again.

On concluding the Indus waters negotiations in 1960, then Indian prime minister, Jawaharlal Nehru, spoke of the treaty as “a happy symbol not only in this domain of the use of the Indus valley waters, but in the larger co-operation between the two countries”. The logic is now reversed. The current Indian government has woven water sharing and conflict back together.

Daniel Haines has received funding from United Kingdom Research and Innovation (UKRI) for his work on South Asian history and water politics via a British Academy Postdoctoral Fellowship and an AHRC-ESRC-FCO Knowledge Exchange Fellowship.

Kate Sullivan de Estrada does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.