"Water and blood cannot flow together," Indian Prime Minister Narendra Modi said in his address to the nation after New Delhi and Islamabad agreed to a ceasefire on May 10. "If Pakistan wants to survive, it will have to destroy its terror infrastructure. There is no other way to peace." 

Modi's speech did not mention the Indus Waters Treaty (IWT), but his message rang clear — the fighting may have come to an end but the 64-year-old water-sharing deal with Pakistan will remain suspended, or as the Indian government puts it: "in abeyance."

So far, the water appears to flow as freely as it has for decades, but some reports say India is considering plans to build infrastructure that would allow it to store and divert more water from the Indus River system. 

The Indus is the longest river in South Asia, spanning over 3,000 kilometers (1,864 miles). It includes a complex system of tributaries that flows from Tibet, through divided Kashmir, and into Pakistan, before emptying into the Arabian Sea near Karachi.

Unilaterally pausing the agreement to share its waters was one of the first steps India took in response to Islamist militants killing 26 civilians, almost all male Hindu tourists, in India-administered Kashmir on April 22.

The attack was claimed by a group calling itself the Kashmir Resistance, which India says is also known as The Resistance Front and is linked to Lashkar-e-Taiba (LeT), a UN-designated terrorist organization.

New Delhi accused Islamabad of backing the brutal massacre — a claim Islamabad denies.

"If there are talks with Pakistan, it will be only on terrorism," Modi emphasized in his televised speech. 

Meanwhile, the government in Islamabad announced it would consider any withholding of water "an act of war" as the Indus is the most vital source of water for most of Pakistan's farms and hydropower plants.

Water security in danger?

So what's at stake if one side walks away from a deal once hailed as a rare success story between the two arch-rivals — a treaty that withstood wars, terror attacks, and diplomatic freezes, perhaps until now?

Some experts worry that the entire region's water security could be in danger. 

India is upstream on the Indus from Pakistan — but the river originates in Tibet, under Chinese control. At the same time, India is downstream on the Brahmaputra River, which begins in China as the Yarlung Tsangpo and supplies freshwater to millions in northeastern India — making it vulnerable to decisions made upstream.

Others point out that India has only put the treaty "in abeyance" — a legal gray zone which is reversible, and could be seen as a measured diplomatic tool.

India's move to use the IWT as geopolitical leverage "undermines the legal integrity of such treaties," said Farhana Sultana, a water, climate and development expert with research experience in South Asia.

"These treaty violations and suspensions can have ripple-on deleterious (harmful) effects across and beyond the region for the examples they set," Sultana told DW, adding that "any unilateral suspension of a treaty on transboundary international rivers pose grave threats to regional security." 

Eroding trust among neighbors 

Sultana, a professor in the department of geography and environment at the US-based Syracuse University, warned that India's government might also be tempted to prioritize its own water needs over those of its eastern neighbor Bangladesh if the treaty suspension proves to be an effective tool in the case of Pakistan.

India shares the Ganges River basin with Bangladesh under the Ganga Water Treaty signed in 1996 and it is set for renewal next year.

Diplomatic relations between New Delhi and Dhaka have been strained since former Bangladeshi Prime Minister Sheikh Hasina fled to India in 2024 after being ousted from office.

Another expert on transboundary water resources and international law, who asked not to be named, agreed with Sultana's assessment.

"Transboundary water treaties create trust and predictability for the riparian states, and have typically been separated from other issues. The unilateral suspension raises serious concerns for all states in the region," the expert said.

"For India it also raises serious concerns as to the future relations with its other neighbors, particularly Bangladesh and China, as trust will be eroded. China is a strong ally of Pakistan," the expert added.

China has significant investments in Pakistan's hydroelectric infrastructure on the Indus River. It is also investing in the management of the Teesta in Bangladesh — a river which originates in India. The region is crucial for China's Belt and Road Initiative, a massive infrastructure project launched in 2013 by President Xi Jinping to boost China's economic and political influence. 

A legal gray zone

The IWT's framework — negotiated over nine years and uniquely mediated by the World Bank — includes no provision for withdrawal. At the same time, it establishes a multi-tiered dispute resolution system that allows India and Pakistan to resolve disagreements and amend the treaty, but only with mutual consent.

The treaty is strictly bilateral and does not fall under the Vienna Convention on the Law of Treaties (1969), which sets out rules for how parties can manage and terminate agreements.

The IWT also does not address the possibility of "abeyance" — India's chosen phrase.  So, while India hasn't officially quit the treaty, it's also not fully operating under its framework — creating a legal gray area.

Gabriel Eckstein, water law and policy expert, told DW that the move hurts India's previously maintained "moral high ground." 

He added that the consequences go even further than that. "International water law is a function of state practice, meaning a bunch of states have done this for so long in a certain way that everybody starts to say that's the law. But now we have certain states veering, it's going to start to weaken what we understood as international water law and start questioning it," Eckstein said.

His argument points to the 1997 UN Convention on the Law of the Non-Navigational Uses of International Watercourses requiring countries to use shared rivers fairly and avoid causing significant harm.

India hasn't signed the convention but generally recognizes its principles and follows them in practice.

The Observer Research Foundation, an Indian think tank, points out that India's move is not without precedent. Advocate Nishant Sirohi writes that there are "limited but notable" examples of states suspending treaty obligations in response to extraordinary circumstances. 

One of them happened as recently as 2023. The US partially suspended the New START Treaty on nuclear arms reduction with Russia in response to non-compliance, a move which could legally be reversed if Russia fulfilled certain requirements.

That is "similar to India's current approach on the IWT," he wrote. 

'Smart, subtle politics'

Anamika Barua, a water security expert and professor at the Indian Institute of Technology in the eastern city of Guwahati, says wider concerns about a treaty violation are misplaced. 

"Had India suspended the treaty, it would have sent the wrong signal. But it has specifically used the term 'abeyance,' as if to give some time to Pakistan to look into its conduct, and tell the entire world that if Pakistan meets its requirement maybe we will go back to where we were," she told DW.  "It's very smart and subtle politics."

This also takes away the point of India having acted unilaterally. "India will say we are not (walking away). We have only told them," she said.

In April, India's Water Resources Minister C R Patil announced that India was working on a short, medium and long-term plan to ensure "not even a drop of water from the Indus River goes to Pakistan." While the plans were not clearly outlined, media reports say it involves diversion in the short-medium term and building hydroelectric dams in the long term.

Barua is concerned that the move may not achieve its intended goals. "In the short term, stopping the river's flow could be difficult without the necessary infrastructure," she said.

"And in the long run, India must avoid building large dams on the Indus system that could harm the river's ecosystem and affect downstream communities."

Where do we go from here? 

The experts DW spoke to agree on one thing — that India and Pakistan will have to go back to diplomatic channels to eventually reinstate the treaty. 

Eckstein, for instance, does not believe there is a legal way forward. 

The World Bank can only act as a mediator within the framework of the treaty which India has now put aside. Islamabad could register a case at the International Court of Justice but India only recognizes its jurisdiction in very specific, pre-outlined cases. If there's no specific agreement taking India to the international court, "India could just wave it off," he said.

Pakistani Prime Minister Shehbaz Sharif said he was ready to engage in peace talks with India, which will inadvertently involve the IWT.

India has been trying for years to bring Pakistan to the table to renegotiate the treaty, which India's government believes is inconsiderate of India's growing population and water needs. If talks really ensue, they will likely reimagine the distribution of the contentious waters.

Old or reworked, a functioning Indus Waters Treaty is critical — especially for India and Pakistan, both of which are bearing the brunt of climate change and mounting pressure on their freshwater resources.

Edited by: Srinivas Mazumdaru