In 1954, Calcutta recorded the maximum temperature in its history — 43.3 degree Celsius — during April. After 54 years, the record seems to be under threat. But is the recent hot spell merely a meteorological event? Environmentalists believe climate change could be the reason.

“Extreme weather is definitely linked to climate change,” says Dipak Chakrabarty, the chief scientist of the state pollution control board.

According to G.C. Debnath, the director of the weather section at the Alipore meteorological centre, changing climate in central India has been modifying the local weather.

The experts feel that Calcutta is vulnerable because of the heat island phenomenon — high temperature in certain pockets. “As there is little green cover in the city, there is little scope of dissipation of heat released from the surface. On top of that, metalled roads and concrete structures absorb a lot of heat,” says a scientist.

“Horizontal circulation of air is severely hampered by houses, creating pockets of heat. There are areas in the city where the temperature is 3-4 degrees higher than the average temperature,” he adds.

Anyone travelling from north Calcutta to south Calcutta, which has far more greenery, will vouch for the theory.