Rains cleanse city air, pollution level dips

The heavy rains that lashed the city for the past two days brought down Kolkata's pollution level to a great extent, an official of the West Bengal Pollution Control Board (WBPCB) said on Monday.

While the PM 2.5 was 29 Air Quality Index (AQI) at the automated air monitoring station at the Fort William in central Kolkata at 2 pm, it was 19 at Jadavpur in the southern parts of the city during the time, a WBPCB official said.

PM is the Particulate Matter, and 2.5 is the diameter measurement of the particulate which is being 2.5 micrometre or less.

At Rabindra Sarobar area also in south Kolkata, the automated air monitoring station showed PM 2.5 at 16 at 2 pm.

The index reading was described as 'good' by environmentalists.

The official said while the PM 2.5 hovered around 30.5 AQI on an average in July as per the readings in different air monitoring stations, it went down to 13.5 on an average in the month of August.

Environmentalist S M Ghosh, however, said the substantial drop in PM 2.5 in THE third week of August is a temporary phase.

"Yes, there has been more than 50 per cent drop in air pollution due to heavy rainfall. It's a natural cleaning process without any air pollution control equipment. But this is nothing but a temporary phase," he said.

"Rain can help to settle down the pollutants on the surface. Rain also cleans the plant leaves and they perform better for carbon mitigation and oxygen generation," he said.