Indus River system and the debate on Indus Water Treaty

Suspension of the Indus Waters Treaty is among the retaliatory steps India announced following the Pahalgam terror attack on April 22,2025 in which terrorists with links to Pakistan killed 26 people. The decision triggered debates about the treaty and potential future course of actions.

The 64-year-old Indus Water Treaty was last in the news over India’s push to renegotiate it and Pakistan’s objections to the design features of two hydroelectric projects (HEP) under construction in Jammu and Kashmir – the Kishanganga HEP on Kishenganga, a tributary of the Jhelum, and the Ratle HEP on the Chenab.

In light of recent developments, it becomes important to revisit the Indus Water Treaty and understand the Indus River System: its origin, course, tributaries and so forth. Let’s first have a brief overview of the treaty.

Indus Water Treaty

India and Pakistan signed the Indus Water Treaty on September 19, 1960 to ensure the distribution of waters of the Indus and its tributaries. It was signed in Karachi by then Prime Minister Jawaharlal Nehru and then Pakistan President Ayub Khan.

In the context of the treaty, Pakistan became the lower riparian state – a place where the river ends – and India the upper riparian state – where the river originates. According to this treaty, India got exclusive rights over the three eastern rivers – Ravi, Sutlej and Beas – amounting to around 33 million acre-feet (MAF), or approximately 20% of the total water of the Indus river system. Pakistan got control over the three western rivers – Indus, Jhelum and Chenab – receiving around 135 MAF, or 80% of the total water. 

However, India can use the water of western rivers for specified domestic, non-consumptive and agricultural purposes. India has also the right to generate hydroelectricity through run-of-the-river (RoR) projects, subject to specific criteria for design and operation.

Article IX of the treaty contains the dispute resolution mechanism. It is a three-tier process: First, disputes are addressed through the Permanent Indus Commission (PIC), comprising representatives from both countries; then through the World Bank-appointed Neutral Expert, and as a last resort, through the Permanent Court of Arbitration.

Indus River system 

A river, along with its tributaries, is called a river system. The Indus River system comprises six rivers: Indus, Jhelum, Chenab, Ravi, Beas, and Sutlej. The Indus and Sutlej are antecedent rivers, meaning they existed even before the formation of the Himalayas and cut deep gorges after originating in the Tibet region. The other four rivers – Jhelum, Chenab, Ravi and Beas – originate in India.   

The Indus Basin extends across four countries, namely China, India, Pakistan and Afghanistan. In India, the basin spans the Union Territories of Ladakh and Jammu and Kashmir as well as Chandigarh and the states of Himachal Pradesh, Punjab, Haryana and Rajasthan. The total drainage area of the basin is approximately 3,21,289 sq. km, accounting for nearly 9.8% of India’s total geographical area.

Western Rivers 

The Indus River originates from the trans-Himalayan range of Kailash (in Tibet) near Mansarovar Lake, where it is known as ‘Singi Khamban’ or the Lion’s Mouth. Flowing westward, it enters India at Demchok in Ladakh. In India, the length of the Indus River is approximately 1,114 kilometres and it flows between Ladakh and Karakoram ranges in the Union Territory of Ladakh. 

The main right bank tributaries of the Indus River are the Shyok (originates from Rimo Glacier), the Shigar, and the Gilgit, while Zaskar, and Hanle are its left bank tributaries. It runs a total of 2,880 kilometres before falling into the Arabian Sea near Karachi, Pakistan. ‘The Indus River Dolphin’, an endangered species as per the International Union for Conservation of Nature (IUCN) Red List, is found mainly in the Indus River.

The Jhelum River (252 km) originates from a spring at Verinag near the Pir Panjal and flows through Wular Lake in Srinagar before entering Pakistan. It joins the Chenab near a place called Jhang in Pakistan. The Chenab River, the largest tributary of the Indus, has a length of 1,180 km in India. It is formed by the confluence of the Chandra and Bhaga rivers at Tandi in Keylong, Himachal Pradesh. 

Eastern Rivers 

The Ravi River (95 km) originates from the Kullu Hills near Rohtang Pass in Himachal Pradesh and merges with Chenab at Sarai Sidhu in Pakistan. The Beas River (354 km) rises from the Beas Kund (elevation: 4,000 meter above sea level) near Rohtang Pass in Himachal Pradesh. It flows through the Kullu Valley and meets Sutlej near Harike in Punjab in India. The Harike Barrage was built in 1952, which diverts water for the Indira Gandhi Canal system. 

The Sutlej River (676 km) is an antecedent river originating from Rakas Tal (elevation: 4,555 m above sea level) near Mansarovar in Tibet. It is known as Langchen Khambab in Tibet before entering India near Ropar. 

To utilise the waters of the eastern rivers, India has built the Ranjit Sagar Dam on Ravi, the Bhakra Dam on Sutlej and the Pong and Pandoh Dam on Beas. Some other important projects on these rivers include the Beas-Sutlej Link, the Madhopur-Beas Link and the Indira Gandhi Canal Project. With the help of these projects, India utilises nearly 95% of the waters of the eastern rivers. 

However, it is some of India’s projects on the western rivers that Pakistan has raised objections to over time. India’s important projects on the western rivers include the Salal Dam Project, the Baglihar Hydropower Project, the Pakal Dul Project, and the Kiru Project, all on the Chenab River, while the Tulbul Project is located on the Jhelum River in Jammu and Kashmir.

Why India seeks renegotiation of Indus Water Treaty

In July 2022, the Parliamentary Standing Committee on Flood Management and International Water Treaties presented its report, and observed that the Indus Water Treaty signed in 1960 was based on the available knowledge and circumstances of that time. It recommended that the Indian government take necessary diplomatic measures to renegotiate the treaty in light of present-day challenges such as global warming, climate change, water availability, and environmental impact. 

In August 2024, India formally notified Pakistan under Article XII (3) of the treaty, seeking review and renegotiation on the basis of present challenges such as population growth, climate change, and the alleged misuse of dispute mechanisms by the neighbouring country.

Unlike the Ganga and Brahmaputra River systems, the Indus River system has the largest glaciated area and is mostly dependent on solid precipitation and glacier meltwater. However, current climate change is presenting challenges related to water availability and distribution in the basin. Given the risks of global warming, both India and Pakistan remain vulnerable to these changes. 

Therefore, while the Indus Water Treaty has been a diplomatic success and has withstood periods of heightened tensions between the two countries, “fundamental and unforeseen changes in circumstances”, reportedly highlighted by India in its September 2024 notification, necessitate a need to revisit the Treaty.

Post Read questions

Why is the Indus River system significant for India and its neighbouring countries?

What are the major dams built by India on the eastern rivers of the Indus system?

What are the key water management projects linking the Beas and Sutlej rivers?

How much of the eastern rivers’ water does India utilise, and through which projects?

Why has Pakistan raised objections to some of India’s projects on the western rivers?

(Abhinav Rai is a Doctoral candidate at the Department of Geography, Delhi School of Economics, University of Delhi.)

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