2021 Diwali Pollution: Worst in Delhi’s Recent History?

What effect did 2021 Diwali have on Delhi air pollution? We previously discussed Diwali’s serious impact on Delhi air pollution. But how did 2021 Diwali pollution compare to past years?

Diwali firecracker air pollution PM2.5

Analyzing 2022 Diwali Air Pollution in Delhi

To get to the bottom of this, the Smart Air team in India analyzed PM2.5 data from the US Embassy in Delhi and data I collected myself to track air pollution before, during, and after Diwali. 

2022 Diwali Pollution

During 2022 Diwali, I recorded PM2.5 air pollution levels in Delhi before, during, and after the holiday. As shown in the graph below, PM2.5 levels skyrocketed as the holiday kicked off and fireworks went off. Over the following 12 hours, pollution levels gradually returned to Delhi’s average (but still extremely dangerous) pollution levels.

2021 Diwali Pollution

Let’s take a look at the PM2.5 data published by the US Embassy in Delhi during Diwali in 2021. PM2.5 spiked during Diwali by over 100% compared to the days prior. Delhi PM2.5 levels were already hovering around 25 times higher than the WHO recommended limit during the 3 days prior. But once Diwali started, levels got to over 60 times the WHO recommended limit.

2020 Diwali Pollution

In 2020, Delhi’s air quality peaked during Diwali day with PM2.5 levels crossing WHO’s recommended limit. The air quality did improve a day after Diwali with a daily average reading of 257 ug/m3 which is over 25 the WHO recommended limit.

2019 Diwali Pollution

In 2019, Delhi’s air quality didn’t change much before and after Diwali where PM2.5 levels peaked at 188 ug/m3 compared to 176 ug/m3 on Diwali day.

2018 Diwali Pollution

2018 saw a big change in air quality with PM levels degrading to 3x times a day after Diwali. Just after Diwali, the PM2.5 levels averaged 454 ug/m3 which is 4.5 times the WHO safe limit.

2017 Diwali Pollution

Delhi’s air quality level averaged over 1000 ug/m3 just three days before Diwali in 2017. Delhi’s PM levels were whopping 100 times WHO recommended limit. Though Delhi saw some respite as air quality improved further. However, just a day after Diwali the PM2.5 levels again reached the hazardous level of 575 ug/m3.

2016 Diwali Pollution

In 2016, the quality was nearly three times worse a day after Diwali with PM2.5 levels reaching a daily average of 998 ug/m3

Table-1: Delhi’s PM2.5 Daily Average Before, On, and After Diwali

Year3 Days Before2 Days Before1 Day BeforeDiwaliAfter Diwali% Change

PM2.5 is of particular interest because these tiny particles are small enough to enter the bloodstream and enter our organs causing heart disease, cancer, and other health problems. The picture below shows how small these pollution particles are.

PM2.5 India

Bottom Line: 2021 Diwali Air Pollution Levels

The PM2.5 levels in Delhi during Diwali were 94% higher in 2021 compared to 2020. For each of the last 5 years, Delhi air quality during Diwali has increased manyfold after the start of the festival.

Smart Air

How I Protect Myself During Diwali and Delhi’s Winters

Despite the harms of PM2.5, studies have found that wearing masks prevents physiological harm to the body. Also using air purifiers in your home has been shown to have positive effects on blood pressure, inflammation, and immune response.

Smart Air is a certified B Corp committed to combating the myths big companies use to inflate the price of clean air.

Smart Air provides empirically backed, no-nonsense purifiers and masks, that remove the same particles as the big companies for a fraction of the cost. Only corporations benefit when clean air is a luxury.

Check out the Sqair!

Free Guide to Breathing Safe

Want to learn more about breathing clean air? Join thousands more and stay up to date on protecting your health.

Notify of

Inline Feedbacks
View all comments
Smart Air low cost purifiers

Smart Air is a social enterprise and certified B-Corp that offers simple, no-nonsense air purifiers and provides free education to protect people from the harms of air pollution. We are proud to be the only certified B-Corp dedicated to fighting air pollution.

Certified B-Corp air purifier company