Take a look at the essential events, concepts, terms, quotes, or phenomena every day and brush up your knowledge. Here’s your UPSC Current Affairs knowledge nugget for today on Indus waters Treaty and Indus River System.India on May 16 rejected the “so-called award” issued on May 15 by the “illegally constituted so-called” Court of Arbitration (CoA) regarding disputes with Pakistan over the Indus Waters Treaty (IWT). Responding to media queries, Ministry of External Affairs official spokesperson Randhir Jaiswal said India has never recognised the establishment of this “so-called” CoA. “Any proceeding, award, or decision issued by it is null and void. India’s decision to hold the Indus Waters Treaty in abeyance remains in force,” he said. In this context, it becomes important to revisit the Indus Water Treaty and understand the Indus River System. Key Takeaways:Indus Waters Treaty (IWT)1. 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.2. The treaty has 12 Articles and 8 Annexures (from A to H). As per the provisions of the treaty, India got exclusive rights over all the water of “Eastern Rivers”— Sutlej, Beas and Ravi — amounting to around 33 million acre-feet (MAF), or approximately 20% of the total water of the Indus river system.3. Pakistan got control over the three “Western Rivers”— Indus, Jhelum and Chenab – receiving around 135 MAF, or 80% of the total water.4. 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.Story continues below this ad5. 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.6. Notably in January 2023, India issued a notice to Pakistan seeking a “modification” of the treaty. This was the first such notice in the more than six decades of the IWT’s existence.7. India upped the ante in September 2024 by issuing another formal notice to Islamabad, this time seeking the “review and modification” of the IWT. The word “review”, according to experts, effectively signals New Delhi’s intent to revoke and renegotiate the treaty, which will turn 65 this year. 8. India decided to keep the IWT in abeyance after the April 22 Pahalgam terror attack, in which terrorists killed 26 people and injured another 10.Story continues below this adIndus River system1. 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. 2. The Indus Basin extends across four countries, namely China, India, Pakistan and Afghanistan.3. 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. Western Rivers1. 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, it flows between Ladakh and Karakoram ranges in the Union Territory of Ladakh. 2. 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. Story continues below this adFYI: ‘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.3. 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. 4. 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 Rivers1. The Ravi River (95) originates from the Kullu Hills near Rohtang Pass in Himachal Pradesh and merges with Chenab at Sarai Sidhu in Pakistan. 2. 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. 3. 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. Story continues below this adBEYOND THE NUGGET: Key Dam and Canal Projects on the Eastern Rivers 1. 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. 2. 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. 3. 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.Post Read QuestionWith reference to the Indus river system, of the following four rivers, three of them pour into one of them which joins the Indus directly. Among the following, which one is such a river that joins the Indus direct? (UPSC CSE 2021)(a) Chenab(b) Jhelum(c) Ravi(d) SutleStory continues below this adAnswer Key(Sources: IWT: India rejects ‘so-called’ arbitration award as ‘null and void’, Indus River system and the debate on Indus Water Treaty) Click Here to read the UPSC Essentials magazine for May 2026. Share your views and suggestions in the comment box or at manas.srivastava@indianexpress.com Subscribe to our UPSC newsletter. Stay updated with the latest UPSC articles by joining our Telegram channel – Indian Express UPSC Hub, and follow us on Instagram and X.