"El Niño is not uniformly a drought signal for India." Examine with reference to the Northeast Monsoon over Tamil Nadu.

El Niño is the warm phase of ENSO. It recurs every 2–7 years, when Pacific waters off Peru and Ecuador warm above average. On average, it has brought deficient rainfall and droughts to India [1]. Yet Tamil Nadu, which is fed mainly by the Northeast Monsoon (NEM, Oct–Dec), shows a "strikingly different pattern" [1]. El Niño is therefore a regional drought signal, not a national one.

Why El Niño means drought for most of India

• The El Niño–deficit link works mainly through the Southwest Monsoon (June–Sept), the main source of rain for most of the country [1].
• The all-India average reflects these states and hides regions with a different rainy season.

Why Tamil Nadu diverges

• Different drivers: the NEM depends on Bay of Bengal conditions, the Indian Ocean Dipole (IOD) and Nov–Dec cyclonic systems [1].
• Pressure gradient between the Bay of Bengal and the Arabian Sea pushes moist air into coastal T.N. [1].
• Warmer Bay waters in strong El Niño years raise evaporation and moisture supply [1].
• Cyclonic circulations in Nov–Dec trigger intense, localised rain [1].
• Example: despite a "super" El Niño in 2026 (~2 °C warming against a typical ~0.5 °C), IMD forecast normal to above-normal NEM rain for southern T.N. [1].

Limits of the exception

• IOD effects vary: a positive IOD can offset El Niño's drying, but IOD–ENSO interactions differ between events [2][3]. In 2026 the IOD is neutral [1].
• A super El Niño has few past analogues, so patterns from average years may not hold.
• Surplus is not always a benefit: concentrated downpours raise urban flood risk, and the forecast covers only southern T.N. [1].

Implications for planning

• Region-specific advisories for NEM farmers instead of a single national drought advisory.
• Dual reservoir planning: store water for lean months but keep room to absorb floods.
• Impact-based, dynamic forecasting: IMD revises outlooks as Bay depressions form [1], and district plans should follow these updates.

El Niño's effect on India thus depends on season and region. It is a deficit signal for Southwest Monsoon states but an uncertain, often wet, signal for NEM-fed Tamil Nadu. Moving from all-India averages to sub-regional forecasts, and preparing for drought and flood together, will turn ENSO science into resilience and advance SDG 13 (climate action).