The Indus Water Treaty: What India can and cannot do by ‘suspending’ it

In the wake of the Pahalgam terror attack on tourists, India announced on 23 April that it would hold the Indus Water Treaty ‘in abeyance’. Its immediate impact, the Hindu reported on Friday, is that India will stop sharing hydrological data on the Indus rivers with Pakistan. By implication, it would also mean that India will stop informing Pakistan of any infrastructure it builds on the rivers, such as hydro-electric projects and storage dams.

The Indus Water Treaty has been under strain for the past few years. The Permanent Indus Commission, comprising experts from India and Pakistan, has not met since 2022. In 2023, India had called on Pakistan to renegotiate the treaty in view of changes in population, water requirements, climate change and natural disasters, besides ‘cross border terrorism’. 

The IWT does not allow India to block the flow of water in the Indus, Jhelum and Chenab, or build storage dams. It also requires India to maintain water levels to ensure that there is no untoward flooding in Pakistan. The hydro-electric projects on the Indian side, like the Kishanganga project and Baglihar, generate electricity by diverting the flow of water, called run-of-the-river projects, but do not stop the flow of the rivers.

Pakistan has been accusing India of modifying the design of these projects in order to control the flow of the rivers to Pakistan. India’s alibi is that it modified the designs only to keep the projects running in optimal conditions.

The Hindu report quotes an unnamed scientist affiliated to the Central Water Commission saying, “For India to weaponise the waters of the Indus, it has to completely ignore the IWT. Under the current terms of the treaty, this cannot be done.”

It is also pointed out by experts that building dams on the Indus rivers would be both costly and complicated. It would take time, cost astronomical sums and risk disrupting the ecological balance in the upper reaches. It would also risk flooding areas within India. For all these reasons, Pakistan does not seem to face any imminent danger in the short run.

In the medium and the long-term, however, nobody can possibly hazard a guess. Experts, of course, hope that the situation would de-escalate soon and talks resumed.

India may, however, consider withdrawing from talks on the dispute resolution mechanism. In the medium term, it may change the designs of the existing hydroelectric projects to store more water. It could also engage in flushing the water-bearing tunnels to keep them free from silt and debris in an effort to control the flow of water.

The Indus River Treaty divided the six rivers of the Indus Basin between the two countries. India received the three eastern rivers (Ravi, Beas, and Sutlej). Pakistan received the three western rivers (Indus, Jhelum, and Chenab), which account for the majority (almost 80 per cent) of the shared basin’s water.

India retained the right to use the western rivers for hydropower and limited irrigation, but is not allowed to store or divert their flow in ways that harm downstream access. These deliberately specific constraints are spelled out in the IWT. Between May and September, as snow melts, the Indus, Jhelum and Chenab carry billions of cubic metres of water. The projects on the Indian side do not currently have the capacity to hold back such volumes.

Nearly 80 per cent of Pakistan’s agriculture depends on water from the western rivers. More than water, however, the IWT ensures for Pakistan the predictability needed to build an irrigation and water management system to cope with the dry months. Disruption of water supplies could lead to water scarcity, reduce crop yields, and precipitate domestic unrest, especially in Pakistan’s water-stressed provinces of Punjab and Sindh.