El Niño is a climate pattern that begins with rising sea-surface temperatures in the central and eastern Pacific around the equator, and goes on to affect weather across the globe.

It is the warm phase of a natural cycle called the El Niño-Southern Oscillation, and it typically occurs every two to seven years.

It does not add new heat to the planet. It releases heat the ocean has already stored beneath the surface, which is why strong events often produce some of the hottest years measured.

It shifts rainfall patterns: some regions get unusually heavy rains and flooding while others face drought. Global temperatures tend to run above average.

For India, El Niño is usually linked to drier-than-average conditions and weaker monsoons, which can hit crops and push up food prices. The IMD has linked this year's below-normal monsoon to El Niño risk.

The current event is forecast to peak in December and last until February 2027, and could be the strongest since the 1950s, the WMO says.