Context: The Supreme Court directed the Centre to constitute a tribunal to adjudicate the dispute between Tamil Nadu and Karnataka over the sharing of Pennaiyar river water.
- A Bench, headed by Justice Vikram Nath, directed the Centre to issue a notification to constitute the inter-State water disputes tribunal within a month. “The Centre may place the complaint filed by Tamil Nadu before the tribunal upon its constitution,” the Bench said. This direction of the court comes under Section 5 of the Inter-State River Water Disputes Act of 1956.
- In 2018, Tamil Nadu moved the Supreme Court against Karnataka over its work on dams and diversions structures on the river. Karnataka had no right to utilise the waters of Pennaiyar to the detriment of the people of Tamil Nadu, the State had told the court. Tamil Nadu argued that the flowing of water of an inter-State river was a national asset and no single State could claim exclusive ownership of its water. An 1892 agreement over the river water was “valid and binding” on the party States, it had contended.
- Tamil Nadu had wanted a prohibition on Karnataka from initiating any new schemes in the Pennaiyar basin until a tribunal was constituted by the Centre.
| Category | Details |
| River Identity | Pennaiyar / Thenpennai / Dakshina Pinakini |
| Hydrology | Originates in Nandi Hills (Karnataka); flows through Tamil Nadu to the Bay of Bengal. |
| Primary Parties | Karnataka (Upper Riparian) & Tamil Nadu (Lower Riparian) |
| The Conflict | TN’s 2018 protest against Karnataka’s upstream diversions and dams on the Markandeya River (a key tributary). |
| Legal Foundation | Article 131 (Original jurisdiction of SC) and the Inter-State River Water Disputes Act, 1956. |
| Recent Verdict | February 2026: Supreme Court ordered the Centre to form a Tribunal within 30 days. |
| Socio-Economic Impact | Threats to irrigation and drinking water for 5+ districts in Northern Tamil Nadu. |