One of the most talked-about topics in 2020 is climate change. The awareness around the subject has increased significantly over the past few years. In fact, the 2020 US Presidential election candidates' stance on the matter was as decisive as the policies they promised!

India too, over the past few years, has been trying to do its part in helping the environment. This includes joining the Paris Agreement in 2015 and pledging to bring forth long-term strategies to lower levels of CO2 and other greenhouse gas emissions by 2020. A strategy that a few state governments have adopted to curb air pollution, which has been an uphill climb for cities in India, is by temporarily banning the sale and bursting of firecrackers, especially during festive seasons.

The rising number of COVID-19 patients has also been a factor for the decision. According to health experts, including those from the Indian Medical Association (IMA), bursting of firecrackers can aggravate the condition of COVID-infected patients.

Fireworks cause extensive air pollution in a brief period of time and leave behind metallic compounds like barium, aluminium and chemicals like perchlorates that can contaminate surface as well as groundwater. Another factor that makes fireworks hazardous is that it increases the PM2.5 levels in the atmosphere. PM2.5 refers to atmospheric particulate matter (PM) that has a diameter of fewer than 2.5 micrometres. Studies have shown a connection between exposure to fine particles and chronic diseases concerning heart and lungs like asthma, heart attack and other respiratory problems.

Let's find out the PM2.5 levels in some Indian cities during Diwali.

Shivajinagar, Pune

Pune Municipal Corporation(PMC) had banned the bursting of firecrackers in public places during Diwali and had appealed to the locals to avoid it even in private places. But this appeal seems to have gone unheeded as there was a significant rise in the PM2.5 levels during the days surrounding Diwali. On November 1st, the PM2.5 levels were already at an unhealthy 86 (24-hour average). This rose to 209, 210, 208 on November 12, 13 and 14 respectively.

Colaba, Mumbai, India

The Brihanmumbai Municipal Corporation(BMC) had banned the use of firecrackers in November although the use of 'mild firecrackers' was permitted on Laxmi Pujan. The decision was necessary because air pollution in Mumbai is already a concern. On November 1st, the average PM2.5 level was an astonishing 683. The situation became comparatively better during Diwali when the PM2.5 levels were at 350, 643, 436, 153 on November 12, 13, 14 and 15th respectively.

Mundka, Delhi, Delhi, India

Air pollution has almost become a connotation to Delhi as city/UT has been struggling to curb the air pollution for years now. According to IQAir, a Swiss air technology company, Delhi, as of November 15, has the most polluted air in the world. On November 1st, the average PM2.5 level was already at a hazardous 333 which remained more or less the same during the Diwali holidays. The PM2.5 levels were at 339, 266, 324, 510 on November 12, 13, 14 and 15th respectively. Delhi CM Arvind Kejriwal had banned the use of firecrackers in the national capital on November 5 but there were reports of firecrackers bursting, according to PTI.

BTM, Bangalore, India

On November 6, Karnataka CM BS Yediyurappa had announced the ban on the use of firecrackers in the state although the sale and bursting of 'green crackers' will be allowed in the state during Diwali. This ban seemed to have had an effect as Bangalore fared well in comparison to other cities in this list. The average PM2.5 level in the city on November 1st was at 82 which dropped down to 76,71,68,67 on November 12, 13, 14 and 15th respectively.

Ballygunge, Kolkata, India

The Calcutta High Court on November 5 ordered a ban on the sale and bursting of all kinds of crackers or fireworks for Kali Puja, Diwali, and Chhatpuja in West Bengal. The ban, which although didn't make things better, did manage to keep the air pollution in check during the Diwali season. On November 1, the average PM2.5 level in Ballygunge was at 129 and on November 13, 14 and 15 the level was at 132, 115 and 153 respectively.

Maninagar, Ahmedabad, India

Gujarat government had stated that it has no intention on restricting the use of firecrackers during Diwali and Gujarati New Year (which falls on November 16) unless the Centre, National Green Tribunal (NGT) or Supreme Court directs otherwise. This decision has clearly led to worsening of the air quality in the region as the city's PM2.5 level went up to 192, 159, 180 on November 13, 14 and 15 respectively. On the day of the Gujarati New Year, the level went up as high as 242. For comparison, the PM2.5 level on November 1 was at a respectable yet unhealthy 146.

(Data source: CPCB - India Central Pollution Control Board)