‘AQI in Kolkata sees significant improvement’

Kolkata: The air quality index (AQI) in the city witnessed a significant improvement as per records of the seven air quality monitoring stations of the West Bengal Pollution Control Board, thanks to the cloud cover due to depression.

The PM 2.5 levels in the air hovered between 70 and 91, with the lowest at Rabindra Sarobar in South Kolkata at 70 and the highest at Fort William at 91.

As per records, the prominent pollutant PM 2.5 at the automatic station at Administrative Training Institute, Salt Lake on Friday read 37 while at Birla Industrial and Technological Museum at Gurusaday Road it was 35.

The prominent pollutant PM 10 at Victoria Memorial stood at 46 while at Indian Association of Cultivation Science, Jadavpur it read 37.

All of these readings fall under the good category which is a rare phenomenon in winters.

Even at Ghusuri, Howrah which in the recent past has been among the front-runners in pollution, the prominent pollutant PM 10 stood at 60 (satisfactory). Just four days back, at Rabindra Sarobar the AQI stood at 146, at Ballygunge it was 202, at Victoria it was 210 and at Bidhannagar it was 159.

“The significant improvement in the AQI is due to high ventilation co-efficient having an inverse relationship with AQI,” a senior official of West Bengal Pollution Control Board said.

According to environmental activist Somendra Mohan Ghosh, the stomata on the surface of the leaves are free from dust pollutants thus resulting in better nutrients generation with better oxygen supply.

“The AQI level of Sarobar is satisfactory with better oxygen generation by trees,” he added.

An AQI between 0-50 is considered good, 51-100 satisfactory, 101-200 moderate, 201-300 poor, 301-400 very poor, and 401-500 severe.

The AQI in Kolkata usually remains the cleanest during October and starts deteriorating from the beginning of November and during December it remains predominantly in the poor category.