COUGH, cough, cough. Achoo. Those were the sounds on my flight back from celebrating Diwali in Delhi. The air quality was so poor, it was just a film of haze over the city as we took off. 

While many of us are generally aware of the worsening outdoor air quality during Diwali, crop burning, and heavy traffic times, many don’t think about it being an issue inside a building. However, studies consistently rank indoor air pollution amongst the top four environmental health risks to the public as people spend up to 90 per cent of their time indoors where levels of pollutants may be as much as two to five times higher than outdoor levels!

According to the World Health Organisation and UNEP, “environmental factors are a root cause of a significant disease burden [with] urban air pollution kill[ing] approximately 800,000 people annually … and indoor smoke from solid fuels kill[ing] an estimated 1.6million people annually due to respiratory diseases”.

PM2.5 air quality index (AQI) categories

AQI per “level of harm”

According to news reports, “air quality in Patna deteriorated sharply during Diwali [due to the] higher level of emission of harmful gases as well as PM2.5 [the levels of fine particles that cause the most lung damage] due to burning of crackers”, dropping it to a score of “very poor”.

“Muzaffarnagar, Uttar Pradesh recorded the highest air pollution with a score of ‘severe’.” Other NCR cities also made the top 10 list of shame, rated with the highest pollution levels, including Noida, Ghaziabad, Greater Noida, and Gurugram. Delhi was close behind, also rating a “very poor”, thanks to revellers defying the Supreme Court two-hour limit on bursting crackers and requested use of “green crackers” to reduce particulate matter by 30%. Some areas even briefly jumped to “hazardous” during this time. 

Yet, this was distinctly better than it was just a few years ago! Even though it hit “severe” air quality rating the “day after Diwali, it was still 30% better than what was recorded last year”. But, currently, Delhi has been experiencing its longest spell of hazardous air quality partly caused by stubble burning in neighbouring states prompting a public health emergency to be declared.

However, we’re happy to report that some cities got it right this Diwali. Although a number of other factors likely influenced the drop, reported sales of crackers were “down 30% this Diwali and sound crackers crashed by 50%” with consumers shifting to more colourful firecrackers over the crackers producing nothing but smoke and noise. Also, “Pune, Mumbai, and Ahmedabad in the western parts of the country recorded a bearable two-digit AQI”. But Mumbai was the “clear winner across metro cities in India.

Diwali in 2019 was Mumbai’s quietest Diwali in 15 years, indicating rising awareness against the use of noisy firecrackers.

Sunday’s Diwali celebrations in Mumbai generated a decibel level of 112.3, recorded just after the 10pm deadline for bursting of firecrackers, down from 117.8 dB posted at the same time in 2017.” 

The city performed better in terms of air pollution too. They recorded their cleanest Diwali air in five years with PM2.5 rating as “good” during the day and “satisfactory” during the evening. Congratulations, Mumbaikars!

-by Micah Branaman-Sharma

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