The Supreme Court on Monday directed the Union government to constitute a dispute tribunal to adjudicate the dispute between Karnataka and Tamil Nadu over the sharing of water from the Pennaiyar river, The Hindu reported.

A bench of Justices Vikram Nath and NV Anjaria directed the Union government to constitute the tribunal within a month. Tamil Nadu’s complaint in the matter can be placed before the tribunal, it said.

Tamil Nadu had moved the Supreme Court in 2018 through an original suit against Karnataka challenging the construction of check dams and diversion structures on the Pennaiyar river, The Hindu reported.

The state argued that Karnataka had no right to use the river water in a manner detrimental to its interests.

Tamil Nadu contended that the water of an inter-state river is a national asset and that no single state can claim exclusive ownership of it. It said that an 1892 agreement governing the usage of the river water was “valid and binding” on all party states, The Hindu reported.

The state further argued that a river included its streams, tributaries and other watercourses that contribute directly or indirectly to its flow. On that basis, it said the Markandeyanadhi, a major tributary with a catchment area in both states, could not be kept outside the scope of the 1892 agreement.

Any new construction obstructing the flow of the Markandeya river, it argued, was governed by the agreement.

Tamil Nadu had also challenged Karnataka’s position that it was free to construct diversion structures or large dams across the Markandeya river.

During the proceedings in November 2024, the Union government had informed the court that negotiations between the two states had failed to resolve the dispute.

Previously, the Supreme Court had said that under the 1956 Inter-State River Water Disputes Act, a tribunal could be constituted only once the Union government concludes that the dispute cannot be settled through negotiations.

The court had reserved its decision in the matter in December.

In its order on Monday, the bench said that it found no reason to refrain from directing the Union government to constitute the tribunal, PTI reported.