Delhi's air quality during the G20 Summit

The air was cleaner, but particulate matter was above the CPCB safe limits.

Blue skies at Bharat Mandapam, the G20 Summit venue in Delhi (Image: https://www.g20.org/en/)

Before the summit

The good news is that there has been a general improvement in air quality in Delhi since January 2023, compared to previous years. But what about the last few weeks in the run-up to the summit? August was India's driest since 1901 and Delhi had a rain deficit of more than 50 per cent. That is likely to have affected air quality, along with some dust storms. 
 
Data for five major pollutants (PM2.5, PM10, nitrogen dioxide, carbon monoxide and ozone) shows that the levels of three air pollutants fell, while those of two went up. In fact, the levels of PM2.5 and PM10 were higher than the safe limits recommended by the Central Pollution Control Board. 

Data shows that in 2023 the levels of three major air pollutants fell, while those of two went up.

From July 1–September 6, 2023, PM2.5 increased by 4.6 per cent to 37 micrograms/cubic metre and PM10 by 15.7 per cent to 106.1 micrograms/cubic metre, while nitrogen dioxide (NO2), carbon monoxide (CO) and ozone decreased by 11.4 per cent, 1.8 per cent and 28.3 per cent, respectively. 

Air pollutants are known to have devastating health effects. PM2.5 and PM10 (particulate matter) can lead to heart disease, stroke and respiratory diseases. Nitrogen dioxide (NO2) can cause asthma and other respiratory conditions, while ozone (O3), at high levels, can trigger breathing problems and result in lung disease. Carbon monoxide can make it difficult to breathe, cause exhaustion, dizziness and flu-like symptoms, and, at high levels, may even prove deadly. 

But right before the summit, on September 7, the International Day of Clean Air for blue skies, the air in Delhi was, in fact, quite clean and the skies quite blue!

During the summit

How clean was the air over the G20 summit weekend in Delhi? Here's a quick look at data (till 6 pm on September 10) from a monitoring station closest to the venue. 

Data recorded at the Major Dhyan Chand National Stadium station near Pragati Maidan shows that from July 1–September 6, 2023, the concentrations of PM2.5 and PM10 were well above the safe limits prescribed by the Central Pollution Control Board.

The averages for this period were 37.3 micrograms/cubic metre for PM2.5 and 111.7 micrograms/cubic metre for PM10. These levels had gone up from the previous year – by 3 per cent and 17.9 per cent. Ozone, at 15.1 micrograms/cubic metre, had also gone up by 18.1 per cent. While nitrogen dioxide and carbon monoxide levels fell – by 13.1 and 8.9 per cent – the CO concentration was still above the safe limit.  

The levels of PM2.5 and PM10 (particulate matter) near the summit were above the safe limits

The health impacts of exposure to these pollutants are well known. (For more, click here.) A recent study published in the journal Nature Communications shows that consumption in G20 countries contributes to approximately 2 million premature deaths globally due to PM2.5 pollution. And only 11 per cent of these deaths take place outside of G20 countries. (To read the study, click here.) 

So, here's hoping that air pollution made its way into the conversations between world leaders in Delhi!  

September 10, 2023: Delhi’s had the year’s cleanest air

The Indian Express reported that the city’s AQI was 45 yesterday — and that it was 2023’s first ‘good’ air day, according to data from the Central Pollution Control Board. The CPCB’s ‘good’ category means that the AQI is between 0 and 50, and its impacts on health are minimal. Rain on Saturday night and early on Sunday could have affected the AQI. Whatever the reason, we’re not complaining!

Fighting air pollution = Combating GHG emissions

An opinion piece in the journal The Lancet Planetary Earth highlights the important connection between air pollution and climate change. It states that “the chemical species that lead to a degradation in air quality are frequently co-emitted with greenhouse gases”. And because of this, it concludes that both air pollution and climate change, which threaten the health of everyone on the planet, need intersectoral policy and action. This one’s worth a read!