With the future of a crucial water-sharing treaty between India and Pakistan up in the air, one outside party is looking on with keen interest: China.

For 65 years, the Indus Waters Treaty has seen the two South Asian rivals share access and use of the Indus Basin, a vast area covered by the Indus River and its tributaries that also stretches into Afghanistan and China.

For much of that history, there has been widespread praise for the agreement as a successful demonstration of cooperation between adversarial states over a key shared resource. But experts have noted the treaty has long held the potential for conflict. Drafters failed to factor in the effects of climate change, and the Himalayan glaciers that feed the rivers are now melting at record rates, ultimately putting at risk the long-term sustainability of water supply. Meanwhile, the ongoing conflict over Kashmir, where much of the basin is situated, puts cooperation at risk.

With treaty on ice, China steps in

That latest provocation threatening the treaty was a terrorist attack in the Indian union territory of Jammu and Kashmir on April 22, 2025. In response to that attack, which India blamed on Pakistan and precipitated a four-day confrontation, New Delhi temporarily suspended the treaty.

But even before that attack, India and Pakistan had been locked in negotiation over the future of the treaty – the status of which has been in the hands of international arbitrators since 2016. In the latest development, on June 27, 2025, the Permanent Court of Arbitration issued a supplementary award in favor of Pakistan, arguing that India’s holding of the treaty in abeyance did not affect its jurisdiction over the case. Moreover, the treaty does not allow for either party to unilaterally suspend the treaty, the ruling suggested.

Amid the wrangling over the treaty’s future, Pakistan has turned to China for diplomatic and strategic support. Such support was evident during the conflict that took place following April’s terrorist attack, during which Pakistan employed Chinese-made fighter jets and other military equipment against its neighbor.

Meanwhile, in an apparent move to counter India’s suspension of the treaty, China and Pakistan have ramped up construction of a major dam project that would provide water supply and electricity to parts of Pakistan.

So, why is China getting involved? In part, it reflects the strong relationship between Pakistan and China, developed over six decades.

But as an expert in hydro politics, I believe Beijing’s involvement raises concerns: China is not a neutral observer in the dispute. Rather, Beijing has long harbored a desire to increase its influence in the region and to counter an India long seen as a rival. Given the at-times fraught relationship between China and India – the two countries went to war in 1962 and continue to engage in sporadic border skirmishes – there are concerns in New Delhi that Beijing may respond by disrupting the flow of rivers in its territory that feed into India.

In short, any intervention by Beijing over the Indus Waters Treaty risks stirring up regional tensions.

Wrangling over waters

The Indus Waters Treaty has already endured three armed conflicts between Pakistan and India, and until recently it served as an exemplar of how to forge a successful bilateral agreement between two rival neighbors.

Under the initial terms of the treaty, which each country signed in 1960, India was granted control over three eastern rivers the countries share – Ravi, Beas and Satluj – with an average annual flow of 40.4 billion cubic meters. Meanwhile, Pakistan was given access to almost 167.2 billion cubic meters of water from the western rivers – Indus, Jhelum and Chenab.

In India, the relatively smaller distribution has long been the source of contention, with many believing the treaty’s terms are overly generous to Pakistan. India’s initial demand was for 25% of the Indus waters.

For Pakistan, the terms of the division of the Indus Waters Treaty are painful because they concretized unresolved land disputes tied to the partition of India in 1947. In particular, the division of the rivers is framed within the broader political context of Kashmir. The three major rivers – Indus, Jhelum and Chenab – flow through Indian-administered Jammu and Kashmir before entering the Pakistan-controlled western part of the Kashmir region.

But the instability of the Kashmir region – disputes around the Line of Control separating the Indian- and Pakistan-controlled areas are common – underscores Pakistan’s water vulnerability.

Nearly 65% of Pakistanis live in the Indus Basin region, compared with 14% for India. It is therefore not surprising that Pakistan has warned that any attempt to cut off the water supply, as India has threatened, would be considered an act of war.

It also helps to explain Pakistan’s desire to develop hydropower on the rivers it controls. One-fifth of Pakistan’s electricity comes from hydropower, and nearly 21 hydroelectric power plants are located in the Indus Basin region.

Since Pakistan’s economy relies heavily on agriculture and the water needed to maintain agricultural land, the fate of the Indus Waters Treaty is of the utmost importance to Pakistan’s leaders.

Such conditions have driven Islamabad to be a willing partner with China in a bid to shore up its water supply.

China provides technical expertise and financial support to Pakistan for numerous hydropower projects in Pakistan, including the Diamer Bhasha Dam and Kohala Hydropower Project. These projects play a significant role in addressing Pakistan’s energy requirements and have been a key aspect of the transboundary water relationship between the two nations.

Using water as a weapon?

With it’s rivalry with India and its desire to simultaneously work with Pakistan on numerous issues, China increasingly sees itself as a stakeholder in the Indus Waters Treaty, too. Chinese media narratives have framed India as the aggressor in the dispute, warning of the danger of using “water as a weapon” and noting that the source of the Indus River lies in China’s Western Tibet region.

Doing so fits Beijing’ s greater strategic presence in South Asian politics. After the terrorist attack, China Foreign Minister Wang Yi reaffirmed China’s support for Pakistan, showcasing the relationship as an “all-weather strategic” partnership and referring to Pakistan as an “ironclad friend.”

And in response to India’s suspension of the treaty, China announced it was to accelerate work on the significant Mohmand hydropower project on the tributary of the Indus River in Pakistan.

Chinese investment in Pakistan’s hydropower sector presents substantial opportunities for both countries in regards to energy security and promoting economic growth.

The Indus cascade project under the China-Pakistan Economic Corridor initiative, for example, promises to provide cumulative hydropower generation capacity of around 22,000 megawatts. Yet the fact that project broke ground in Gilgit-Baltistan, a disputed area in Pakistan-controlled Kashmir, underscores the delicacy of the situation.

Beijing’s backing of Pakistan is largely motivated by a mix of economic and geopolitical interests, particularly in legitimizing the China-Pakistan Economic Corridor. But it comes at the cost of stirring up regional tensions.

As such, the alignment of Chinese and Pakistani interests in developing hydro projects can pose a further challenge to the stability of South Asia’s water-sharing agreements, especially in the Indus Basin. Recently, the chief minister of the Indian state of Arunachal Pradesh, which borders China, warned that Beijing’s hydro projects in the Western Tibet region amount to a ticking “water bomb.”

To diffuse such tensions – and to get the Indus Waters Treaty back on track – it behooves India, China and Pakistan to engage in diplomacy and dialogue. Such engagement is, I believe, essential in addressing the ongoing water-related challenges in South Asia.

Pintu Kumar Mahla is affiliated with the Water Resources Research Center, the University of Arizona. He is also a member of the International Association of Water Law (AIDA). Pintu Kumar Mahla has not received funding related to this article.