Chennai's AQI dropped to hazardous levels during Deepavali

CHENNAI: Despite the promotion of green crackers and time restrictions, Chennai city's air pollution levels dropped to hazardous levels during Deepavali.

According to Tamil Nadu Pollution Control Board (TNPCB), the city’s Air Quality Index (AQI) ranged from 345 and 786 observed on October 24 from 6 am to October 25 at 6 am.

Sowcarpet registered the highest pollution with an AQI of 786 as against last year’s 371. Nungambakkam followed suit with 563, Valasaravakkam with 545, Triplicane posted 503 and Thiruvottiyur with 436. Besant Nagar, like last year, recorded the least AQI value of 345 and T Nagar followed with 372.

According to the AQI standards set by the Central Pollution Control Board (CPCB), AQI between 401 and 500 is considered severe, affecting healthy people and seriously impacting those with existing diseases. If values are between 301-400, they may cause respiratory illness in people with prolonged exposure. Anything between 201 and 300 is considered poor causing breathing discomfort to people.

TNPCB chairperson, in the statement, attributed the high pollution level to a large number of people indulging in very active bursting of firecrackers (mainly night crackers and sky shots) and high relative humidity and low wind speed. “The climatic condition is not conducive for the effective dispersion of the smoke emanating from the bursting of crackers,” the statement added.

G Sundarrajan of Poovulagin Nanbaragal, an environmental NGO, said that residents of Chennai on Monday breathed as much toxic smoke as if they smoked 31 cigarettes a day. "The AQI in the city dropped to 786 at Sowcarpet which is equal to a person smoking as many as 31 cigarettes in a day," he said.

The noise levels recorded at all seven stations on Deepavali day were higher than the National Ambient Noise Standards of 55dB during the day and 65 dB during the night. “During the Deepavali day, the lowest noise level value observed was 66.0 dB (A) at Besant Nagar and the highest value was 79.7 dB (A) at Thiruvottiyur. The noise levels observed on Deepavali day are higher than National Ambient Noise Standards,” the statement said.

Even a day after the celebrations, the air quality in the city was ‘poor. As per the TNPCB data as of Tuesday noon, most of the observation points in the city and its surroundings generally had remained at poor levels. PM 2.5 (particulate matter less than 2.5 microns in diameter) was the main pollutant.