A moving Bay system triggered in five hours the heaviest rain Kolkata has received in 40 years, killing at least 9 people, all of them electrocutions, and knocking the wind out of the sails of a city gearing up for its biggest festival — Durga Pujo.

The Met office at Alipore recorded 252mm of rain in just five hours. The showers were not something that even a rain-scarred city had known for years.
The last time it rained this much was on September 26, 1986. The Alipore count then was 259.5mm. Record overnight rains flooded roads, hospitals and classrooms. The showers submerged railway tracks, disrupting flights and snapped power in swathes of the city. The Blue Line (north-south) of Metro Railway was disrupted for hours. Offices were empty and almost every educational institution declared a holiday.

But what caused the deluge in the city? Was Kolkata’s rain shock a cloudburst? Is it linked to climate change?

Story: Debraj Mitra
Video Producer: Shohini Bose
Video Editor: Joy Das