Supreme Court Seeks Karnataka’s Reply to Tamil Nadu’s 20 TMC Cauvery Water Deficit Claim

Supreme Court Examines Cauvery Water Dispute Between Karnataka and Tamil Nadu The Supreme Court on 24 September 2026 asked Karnataka to respond to Tamil Nadu’s plea that it is short of 20 TMC (thousand million cubic feet) of Cauvery water. Both states called the issue “very sensitive” and highlighted their respective hardships. Key Developments Karnataka told the Court it is facing a severe drought but has tried to meet its obligations as an upper riparian state. Tamil Nadu, represented by senior advocate C.S. Vaidyanathan, claimed a deficit of 20.969 TMC and warned that its kharif crop is suffering. The Court gave Karnataka one week to file its response and set the next hearing for 12 October 2026 . Both parties noted the role of the CWRC and the CWMA in tracking the situation. Important Facts • Karnataka recorded 112.729 TMC of inflow between 1 June and 9 September 2026. It released 19.349 TMC through four reservoirs, 3.9 TMC via Anaicut channels, and 3.962 TMC from the Kabini dam, totalling about 140 TMC. • Tamil Nadu normally expects 97.408 TMC in a normal year. It argues it should receive at least 57 % of that (≈59.191 TMC), but has so far received only 35 TMC. • The monsoon has receded, and experts see little chance of further rain in Karnataka, while Tamil Nadu may benefit from the approaching northeast monsoon . UPSC Relevance The dispute illustrates several core UPSC themes: Inter‑state water conflicts – a classic case of federalism, water rights, and the role of the judiciary (GS2). Institutional mechanisms – the functioning of the CWRC and CWMA as examples of expert bodies created to manage shared resources. Environmental challenges – drought and erratic monsoon patterns affect agriculture, water security, and inter‑state relations (GS3). Legal precedents – the Supreme Court’s intervention underscores the judiciary’s role in adjudicating resource disputes. Way Forward • Both states should present detailed data to the CWMA for an impartial assessment. • The Centre may consider a revised water‑sharing formula that accounts for drought severity and seasonal variations. • Strengthening rain‑water harvesting and groundwater recharge in Karnataka could reduce future deficits. • Continuous monitoring of monsoon trends and early warning systems will help both states plan agricultural cycles more effectively.