The Indus Basin and the Indus Waters Treaty

Pakistan is a hydrological state. Its agriculture, food security, energy mix and even ethnic balance are tied to the Indus river system. Understanding the basin, the 1960 Indus Waters Treaty (IWT) and the modern pressures on both is essential for any exam answer on Pakistan's water politics.

The Indus river system

The Indus, the fifth longest river in Asia, rises in Tibet near Lake Mansarovar at over 5,000 m, flows through Indian-administered Ladakh, enters Pakistan via Gilgit-Baltistan and discharges into the Arabian Sea south of Karachi after a journey of roughly 3,180 kilometres.

The basin's six rivers are:

River	Source	Status under IWT
Indus	Tibet	Western — Pakistan
Jhelum	Verinag, Indian-administered Kashmir	Western — Pakistan
Chenab	Himachal Pradesh, India	Western — Pakistan
Ravi	Himachal Pradesh, India	Eastern — India
Beas	Rohtang, Himachal Pradesh	Eastern — India
Sutlej	Tibet, via Himachal Pradesh	Eastern — India

Why water is existential for Pakistan

Three facts establish the centrality of water:

Why the Indus Waters Treaty was negotiated

Partition in 1947 left the headworks of the eastern rivers (Ravi, Beas, Sutlej) on the Indian side, while their downstream irrigation systems were in Pakistan. On 1 April 1948, India briefly stopped the flow of water from Madhopur and Ferozepur headworks — a wake-up call for Pakistan.

The Inter-Dominion Accord (May 1948) restored flows temporarily, but a permanent settlement was needed. The World Bank — at the suggestion of David Lilienthal — took up mediation in 1951. After nine years of negotiation, the Indus Waters Treaty was signed on 19 September 1960 in Karachi by President Ayub Khan and Prime Minister Jawaharlal Nehru, witnessed by World Bank President W.A.B. Iliff.

What the IWT does

The treaty divides the rivers, not the waters:

• Eastern rivers (Ravi, Beas, Sutlej) — Indian use, with unrestricted rights for India.
• Western rivers (Indus, Jhelum, Chenab) — Pakistani use, with limited Indian rights for non-consumptive purposes (run-of-river hydropower, domestic, navigation, fishing) under specific design criteria.

It also created:

• The Permanent Indus Commission (PIC) — two Indus Commissioners (one each from Pakistan and India) meet annually to resolve technical issues.
• A three-tier dispute resolution mechanism: PIC → Neutral Expert (for "differences") → Court of Arbitration (for "disputes").
• The Indus Basin Development Fund — an international consortium financed the construction of replacement infrastructure on the western rivers (Tarbela, Mangla, link canals).

This treaty is one of the great accomplishments of the post-war period, made possible by the spirit of compromise on both sides and by the recognition that water cannot be a weapon.

Replacement works under the treaty

Pakistan built, with international financing, a vast set of replacement works to substitute for the lost eastern rivers:

• Tarbela Dam (1976) on the Indus — the world's largest earth-filled dam at the time.
• Mangla Dam (1967) on the Jhelum, raised in 2009.
• Link canals — Taunsa-Panjnad, Trimmu-Sidhnai, Sidhnai-Mailsi-Bahawal — transferring western water to eastern command areas.

These works fundamentally reshaped the Pakistani irrigation map and made the IWT viable.

The disputes mechanism in action

The IWT has held through three wars (1965, 1971, 1999) and many crises, but its dispute mechanism has been activated repeatedly.

Baglihar (Chenab) — Neutral Expert, 2007

A run-of-river hydroelectric project on the Chenab in Indian-administered Kashmir. Pakistan objected to spillway design and pondage. The Neutral Expert ruled in 2007 that some design changes were required but largely upheld India's project.

Kishenganga (Jhelum) — Court of Arbitration, 2013

The Kishenganga project diverts water from the Kishenganga (Neelum) river — a Jhelum tributary — for hydropower generation. The Court of Arbitration ruled in 2013 that India could proceed but with constraints on drawdown flushing and minimum environmental flows.

Ratle and the current dispute

Pakistan has objected to the Ratle hydropower project on the Chenab. India and Pakistan initially disagreed on whether to use the Neutral Expert or Court of Arbitration procedure. In 2022 the World Bank activated both processes — a first — leading to overlapping proceedings that India has refused to participate in.

The 2023-25 strains

In January 2023 India formally requested modification of the IWT under Article XII(3), arguing that the treaty needs updating in light of climate change, population growth and modern projects. Pakistan declined to renegotiate on the grounds that the treaty has no expiry and modification requires both sides' consent.

After the April 2025 Pahalgam attack, India announced the "suspension" of the IWT — an unprecedented unilateral move that Pakistan called illegal. The exact operational meaning of "suspension" remains unclear, but India has stopped sharing flow data and notification on western-river projects, raising the prospect of long-term treaty breakdown.

Looking forward

For Pakistan, the IWT remains essential — but insufficient. Key tasks for any Pakistani water strategy include:

1. Storage — Pakistan can store only about 30 days of water, against an Indian capacity of 220 days and global norm of 1-2 years.
2. Conservation — irrigation losses run as high as 50-60%; lining of canals and shift to drip/sprinkler systems are urgent.
3. Inter-provincial allocation — the 1991 Water Accord remains contested by Sindh and Balochistan.
4. Adaptation to glacial-flow change — the Hindu Kush-Karakoram-Himalaya cryosphere is shifting under climate change.

The next lesson covers internal Pakistani water politics — the 1991 Accord, the Kalabagh question and the federal-provincial fault lines.