The violence-marred water feud between Karnataka and Tamil Nadu illustrates how water stress is fuelling bitter discord between states over sharing the most vital of all natural resources. The Supreme Court intervened this year too in the Punjab-Haryana dispute in the Indus Basin over the Sutlej-Yamuna Link Canal.

The growing inter-provincial water wrangles draw attention to India’s great water folly in 1960: It signed a treaty that allocated to an enemy state, Pakistan, most of the Indus river system waters, without any quid pro quo. The Indus Waters Treaty (IWT) reserved for India just 19.48% of the total waters of the six-river Indus system.

An emboldened Pakistan, having secured what still ranks as the world’s most generous water-sharing treaty, set its sights on capturing the Indian part of Jammu and Kashmir through which the three large rivers reserved for Pakistani use by the IWT flowed. In more recent years, Pakistan has also found novel ways to turn the IWT into a weapon against India.

From waging conventional wars against India from almost the time it was created to sustaining a protracted proxy war by terror against it, Pakistan has for over a decade now been pursuing a “water war” strategy against India. This strategy centres on repeatedly invoking the IWT’s conflict-resolution provisions to “internationalise” any perceived disagreement so as to mount pressure on India.

In its latest move to corner India, Pakistan has initiated steps to haul it before a seven-member international arbitral tribunal in The Hague for pursuing two hydropower projects in J&K. Twice before in the past decade, Pakistan triggered international intercession by similarly invoking the treaty’s conflict-resolution provisions.

Pakistan’s strategy, coupled with its use of state-reared terrorists, could potentially force India’s hand. If India begins to view the IWT as a liability and sees itself as the suffering loser, little can save the treaty. After all, India has the option in international law to dissolve the lopsided but indefinite treaty. The Anti-Ballistic Missile Treaty was also of indefinite duration but the US unilaterally withdrew from it after Russia opposed its revision.

The withdrawal option, however, cannot be exercised by a risk-averse nation. India may be parched today but there is still no national discussion about how Pakistan is repaying India’s water largesse with blood by sponsoring cross-border acts of grisly terrorism. The water card is probably the most potent instrument India has in its arsenal – more powerful than the nuclear option, which essentially is for deterrence.

India’s belated moves to address the problem of electricity shortages and underdevelopment in J&K by building modestly sized, run-of-river hydropower plants have rankled Pakistan, although the IWT permits such projects (which use a river’s natural flow energy and elevation drop to produce electricity, without the need for any dam reservoir). The treaty requires India to provide Pakistan with prior notification, including design information, of any new project. Although prior notification does not mean the other party’s prior consent, Pakistan has construed the condition as arming it with a veto power over Indian works. To keep unrest in J&K simmering, it has objected to virtually every Indian project. Its obstruction has delayed Indian projects for years, driving up their costs substantially.

Not surprisingly, there have been repeated calls in the J&K assembly for revision or abrogation of the IWT. By gifting the state’s river waters to Pakistan, the treaty has hampered development there and fostered popular grievance.

J&K’s total hydropower-generating capacity in operation or under construction does not equal the size of a single mega-dam that Pakistan is currently pursuing, such as the 7,000 MW Bunji Dam or the 4,500 MW Bhasha Dam. Indeed, while railing against India’s run-of-river projects, Pakistan has invited China to build mega-dams in the Pakistani-occupied part of J&K, itself troubled by discontent, including against the growing Chinese footprint there, especially in Gilgit-Baltistan.

A 2011 report prepared for the US Senate Foreign Relations Committee called the IWT “the world’s most successful water treaty” for having withstood conflicts and wars. The treaty has been a success mainly because of India, which has continued to uphold the pact even when Pakistan has repeatedly waged aggression and fundamentally altered the circumstances of cooperation.

International law recognises that a party may withdraw from a treaty in the event of fundamentally changed circumstances. Pakistan’s continuing use of state-reared terrorist groups against India constitutes reasonable grounds for the injured party to unilaterally withdraw from the IWT. Sustained sponsorship of cross-border terrorism over many years has created fundamentally changed circumstances that undermine the essential basis of India’s original consent to the IWT, while significantly altering the balance of obligations.

The Indus is Pakistan’s jugular vein. If India wishes to improve Pakistan’s behaviour and dissuade it from exporting more terrorists, it should hold out a credible threat of dissolving the IWT, drawing a clear linkage between Pakistan’s right to unimpeded water inflows and its responsibility not to cause harm to its upper riparian. A failure to respect that linkage should free India, for example, to link the Chenab (which has the largest transboundary flow) with the Ravi-Beas-Sutlej system to address water scarcity in its north.