Indus Waters Treaty

The Indus Waters Treaty (IWT) is an historic water-distribution agreement between India and Pakistan negotiated under the auspices of the World Bank to regulate the utilisation of the waters of the Indus River system. Signed in Karachi on 19 September 1960 by Prime Minister Jawaharlal Nehru of India and President Ayub Khan of Pakistan, the treaty sought to provide a durable framework for sharing one of the world’s largest and most complex river basins. For over six decades it was regarded as a successful example of transboundary water cooperation. However, on 23 April 2025 the Government of India suspended the treaty, citing national security considerations following the Pahalgam attack and alleging Pakistan’s involvement in state-sponsored terrorism.

Structure and Allocation of River Waters

The treaty divides the six major rivers of the Indus basin into two categories, effectively allocating exclusive rights over each group to one of the two signatories. The Eastern Rivers—the Ravi, Beas and Sutlej—were assigned for India’s unrestricted use after meeting limited obligations in Pakistan. The Western Rivers—the Indus, Jhelum and Chenab—were reserved for Pakistan, subject to India’s rights to non-consumptive uses and some narrowly defined irrigation.
This arrangement effectively partitioned rather than shared the system. India obtained approximately 30 per cent of the total average flow, while Pakistan received around 70 per cent. India’s rights on the Western Rivers allow activities such as hydroelectric power generation, navigation, floating of property and fish culture, provided that such projects adhere strictly to the technical designs specified in the treaty so as not to impair Pakistan’s water supply.
The treaty includes a safeguard stipulating that any water use by either country cannot be legitimised merely by lapse of time if it infringes on the other party’s rights. The classification of tributaries and distributaries is clearly delineated, ensuring that even minor channels fall under the treaty’s regulatory ambit.

Transitional Arrangements and Financial Provisions

A ten-year transition period enabled Pakistan to construct the necessary works to harness the Western Rivers. During this phase India agreed to continue supplying Pakistan with water from the Eastern Rivers and to provide financial assistance amounting to £62,060,000 (or 125 metric tons of gold under the then-prevailing standard). Even during the 1965 war, India continued water deliveries and financial instalments, reflecting the treaty’s resilience in periods of armed conflict.
The funds facilitated the development of an extensive canal network in Pakistan’s Punjab province, transforming the region into one of the world’s largest irrigated agricultural zones by the early twenty-first century.

Indus Basin Geography and Historical Context

The Indus system originates in the Tibetan Plateau and the Himalayas before flowing across Jammu and Kashmir, Himachal Pradesh, Punjab and Sindh, ultimately draining into the Arabian Sea. Prior to partition, an interconnected irrigation network spanned much of what are now India and Pakistan. The division of British India in 1947, however, left the headwaters within Indian territory and the irrigation infrastructure predominantly in Pakistan, giving rise to immediate tensions.
In 1948 an interim arrangement was established whereby India released water to Pakistan in exchange for payments. Both sides recognised the need for a more permanent settlement, yet bilateral negotiations stalled. Pakistan, apprehensive about upstream control, sought international adjudication whereas India insisted on a bilateral mechanism.

World Bank Mediation and the Path to the Treaty

In 1951 the American administrator David Lilienthal visited the region and proposed a cooperative framework for water development, suggesting that collaboration on water resources could lessen political tensions and eventually facilitate progress on the Kashmir dispute. His ideas influenced the World Bank, which undertook a mediatory role and ultimately facilitated the drafting and signing of the Indus Waters Treaty.

Institutional Mechanisms and Dispute Resolution

The treaty created the Permanent Indus Commission (PIC), composed of one commissioner from each country. The commissioners meet regularly, exchange data, inspect works and attempt to resolve technical matters. The PIC has functioned continuously despite wars and diplomatic ruptures, demonstrating the institutional stability of the treaty framework.
Where disagreements arise, the treaty provides a tiered mechanism: technical questions may be referred to a neutral expert, while legal disputes may be submitted to the Permanent Court of Arbitration. This mechanism has adjudicated several cases, including the Baglihar Dam and Kishanganga Hydroelectric Plant, whose construction India defended within treaty parameters.
The treaty requires prior notification of engineering works and full disclosure of technical data. Instances of prolonged disagreement, such as the Tulbul Navigation Project and the Ratle Hydroelectric Plant, illustrate the limitations of the treaty’s provisions in the face of evolving technologies and shifting geopolitical priorities.

Points of Contention and Compliance Challenges

Pakistan has raised concerns regarding India’s hydroelectric and storage projects on the Western Rivers, claiming that certain designs violate treaty parameters. India, in turn, has not formally pursued treaty violations by Pakistan but maintains objections over groundwater utilisation in the Ravi–Sutlej basin and flood-control works that allegedly alter the hydrological flow into India’s Kutch region.
Some analysts argue that repeated recourse to arbitration could jeopardise the treaty’s viability, especially if interpretations by adjudicating bodies significantly modify the operational balance established in 1960.
Pakistan’s reliance on the Indus system is intensified by declining per-capita water availability and pressures of climate change. The country’s irrigation network, among the largest globally, depends heavily on regulated flows from the Western Rivers. These vulnerabilities shape Pakistan’s strategic concerns regarding upstream developments.

Modern Relevance and Climate Concerns

While widely hailed as one of the world’s most enduring water-sharing agreements, the treaty faces modern challenges. Climate change has altered glacial melt patterns, seasonal flows and flood intensity. Both states acknowledge that technical provisions drafted in the 1950s do not fully account for twenty-first-century hydrological realities or expanding water demands. Calls for updating the treaty to incorporate climate adaptation, groundwater management and cooperative flood response have grown steadily.
The suspension of the treaty by India in 2025 marks a critical turning point. It raises questions about the future of river diplomacy in South Asia and the broader stability of the region’s water-sharing frameworks. Whether this action results in renegotiation, legal contestation or a shift to new bilateral arrangements remains uncertain, but the decision underscores the enduring interplay between water resources and geopolitical tensions in the Indus basin.