TN's 26% Monsoon Deficit and What El Niño Means for the Northeast Monsoon

Why this matters to Tamil Nadu

Tamil Nadu depends on the Northeast Monsoon (October-December) for 48% of its annual rainfall — the highest NEM dependence of any Indian state. A below-normal NEM following a 26% SWM deficit would mean a full-year rainfall shortfall that could push Tamil Nadu's four major reservoirs (Poondi, Chembarambakkam, Red Hills, Cholavaram) into critical levels by January 2027, trigger water rationing in Chennai, worsen the Cauvery dispute's agricultural impact, and drive crop failure across the Samba paddy belt. The IMD forecast arriving this week is not a weather curiosity — it is the key variable for farmers, urban planners, and water managers across the state for the next six months.