Kolkata AQI dips on Diwali amid rain; no escape from noise in Jharkhand

Intermittent rain and warnings of cyclone 'Sitrang' saw air pollution levels dip in Kolkata on Diwali, though the rain gods could not stem fireworks' use and the resulting noise in the capital of neighbouring state of Jharkhand.

Air pollution level across Kolkata on Kali Puja-Diwali evening was "far less" than what it was on the occasion in the last three years, an official of West Bengal Pollution Control Board (WBPCB) said on Tuesday.

The dip in air pollution can largely be attributed to intermittent showers since Monday morning under the impact of cyclone 'Sitrang', he said.

The light rain cleansed the air and prevented a section of revellers to go out and burst firecrackers, the official said.

At Rabindra Sarobar in south Kolkata, the air quality index was 43 at 11 pm, which comes in the 'good' range. The AQI in the same locality was 168 around the same time on last year's Kali Puja.

Similarly, the AQI at an air monitoring station in Jadavpur was 44 on Monday as compared to 244 around the same time on the Kali Puja night of 2021, he said.

Showing a similar trend in the northern parts of the city, the AQI was 39 (good) at Bidhannagar against the year-ago count of 229, which is considered 'poor'.

Environmentalist Somendra Mohan Ghosh said the sound pollution level was, however, high at night in parts of Tollygunge, Jadavpur, Kasba, Jorasanko, Girish Park and Beliaghata in the city, and also in Salt Lake.

"The WBPCB should come out with details about sound pollution due to bursting of crackers in different parts of the city and also on violation of the two-hour window from 8 pm given for bursting of green firecrackers on October 25," he said.

In Jharkhand, sound pollution in Ranchi's silence zone rose 54.22 per cent above the permissible limit on Diwali.

However, if compared to the pre-Diwali level on October 18, a week ahead of the festival, there was a 6.34 per cent increase in noise pollution on average on Monday, the official of Jharkhand State Pollution Control Board (JSPCB) said.

The board monitored sound pollution levels at four locations in the city -- Jharkhand High Court (silence area), Albert Ekka Chowk (commercial area), Kutchery Chowk (commercial area) and Ashok Nagar (residential area) -- for six hours from 6 pm on Monday.

At Albert Ekka Chowk and Kutchery Chowk, the sound pollution levels were 2.33% and 1.96% higher than pre-Diwali figures on October 18 respectively, according to the JSPCB data.

Similarly, Ashok Nagar recorded a 3.06% rise above the pre-Diwali figures, as per data.

"Ranchi's silence zone recorded 69.4 dB between 6 pm and 12 midnight on Diwali against the average permissible limit of 45 dB. Ashok Nagar, a residential area, registered 55.46 dB on average during the period against the permissible level of 50 dB.

"The commercial areas of Albert Ekka Chowk and Kutchery Chowk recorded 75.33dB and 72.76 db respectively on average against the 60 dB permissible limit," JSPCB analyst Ramanand Anjan said.

Ban on firecrackers that produce noise above 125 decibel (dB) has helped curb sound pollution to an extent in the state capital this time, Anjan added.