Air Quality Index at most places in city 'satisfactory' as mercury rises

kolkata: The sudden rise in temperature during Christmas has proved to be a blessing in disguise with the air quality index (AQI) in the city witnessing a significant improvement.

The AQI at almost all the automatic monitoring stations in Kolkata revealed that the city air was satisfactory throughout Tuesday. Even three days back on December 23, the AQI at most places was in above 300 microgammes per cubic metre which falls under the Very Poor category.The reading at 10 am on Tuesday revealed that AQI at Victoria Memorial in the heart of the city was 92, that in Ballygunge was 87 , that in Fort William was 81, in Jadavpur it was 80 while in Rabindra Sarobar it was 62. Only at Bidhannagar and Rabindra Bharati University the AQI was 108 and 147 and that too in moderate category.

"The significant improvement in the AQI is due to high ventilation co efficient having inverse relationship with AQI,"Kalyan Rudra, Chairman of West Bengal Pollution Control Board said.

Even in Ghusuri, Howrah the AQI was 149 very much in moderate range. On December 21, this place had AQI of 430 (severe range) which was the highest in the country. The severe range 400- 500 affects healthy people and seriously impacts those with existing diseases.

"There is 65 to 70 percent fall in the AQI level. The mist canon machine used by the Kolkata Municipal Corporation have been able to settle the minute dust particles and the rise in temperature coupled with wind has had a combined effect in this record fall of AQI,"environmentalist Somendra Mohan Ghosh said.

He however pointed out the phenomenon as a short term gain through nature's sanitise climatic cycle.

The AQI in Kolkata that was cleanest during October in years, had started deteriorating from the beginning of November and during December it was predominantly in poor and very poor category.