Global air quality improves in 2020 but south Asian cities still the top pollutants

by Sumana Sarkar 17 Mar 2021


The 2020 World Air Quality Report by IQAir reveals that Covid-19 lockdowns and behavioural changes on global particulate pollution (PM2.5) levels emerged as a major, exceptional factor influencing air quality during 2020. All Indian cities that were monitored showed air quality improvements compared to 2018, while 63 percent saw improvements compared with 2019. However, India continues to feature prominently in the most polluted cities ranking, with 22 of the top 30 most polluted cities globally.

Though 49 of the 50 of the most polluted cities worldwide are in Bangladesh, China, India, and Pakistan, 84 percent of all monitored countries observed air quality improvements, largely due to measures like lockdown to arrest the spread of Covid-19. Major air quality improvement was seen in Beijing (-11%), Chicago (-13%), Delhi (-15%), London (-16%), Paris (-17%) and Seoul (-16%) in 2020 compared to 2019. However, only 24 out of 106 monitored countries met World Health Organization (WHO) annual guidelines for PM2.5 in 2020.

Climate change continues to affect air quality
2020 is tied with 2016 as the hottest year on record. Wildfires and sandstorms fuelled by the warming climate led to extremely high pollution levels in California, South America, Siberia and Australia. 

In China, 86 percent of the cities in China experienced cleaner air than the previous year in 2020. Despite this, Chinese residents are still exposed to PM2.5 levels more than 3 times the WHO annual guidelines. Hotan in northwestern China ranks as the world’s most polluted city, largely due to sandstorms exacerbated by climate change.

Average particle pollution on the rise
The average particle pollution levels rose by 6.7% in 2020 across United States. Record-breaking wildfires in California, Oregon and Washington caused U.S. cities to comprise 77 of the world’s top 100 most polluted cities in September 2020. 38 percent of American cities did not meet the WHO's guideline for annual PM2.5 levels. This is a significant uptick from the 21 percent of U.S. cities that did not meet the WHO guidelines in 2019.

About half of all European cities exceed the WHO's target for annual PM2.5 pollution in 2020. The highest levels of PM2.5 pollution was found in eastern and southern Europe, with Bosnia Herzegovina, North Macedonia and Bulgaria taking the lead.

Air pollution a major health hazard
Air pollution continues to present one of the world’s biggest health hazards to people everywhere, contributing to about 7 million premature deaths annually and 600,000 of these deaths are children. Compounding this staggering health crisis, air pollution is estimated to cost the global economy upwards of $2.9 trillion per year (3.3 percent of global GDP) due to fossil fuel emissions alone, while also contributing to a range of severe environmental problems.

Frank Hammes, CEO of IQAir pointed out that, “2020 brought an unexpected dip in air pollution. In 2021, we will likely see an increase in air pollution due to human activity, again. We hope this report will highlight that urgent action is both possible and necessary to combat air pollution, which remains the world's greatest environmental health threat."

Avinash Chanchal, Climate Campaigner, Greenpeace India added that, “To see real, long-term improvements in air quality, governments must prioritize clean energy sources such as wind and solar and promote low cost, carbon neutral and accessible transport. Speeding up the transition to clean energy and clean transport not only saves lives, but also dramatically reduces healthcare-related costs.” said.

Lauri Myllyvirta, lead analyst at the Centre for Research on Energy and Clean Air (CREA), who also contributed to the report explained that, "many parts of the world experienced unprecedented, but short-lived, improvements in air quality in 2020, as restrictions related to the Covid-19 pandemic caused a steep drop in fossil fuel consumption. This improved air quality meant tens of thousands of avoided deaths from air pollution. By transitioning to clean energy and clean transport we can realize the same improvements in a sustained way."

The 2020 World Air Quality Report is based on PM2.5 data from 106 countries, that has been measured by ground-based monitoring stations. Of the data sources included in this report, 66.6% of stations were operated by governmental agencies, while the remainder represent monitoring stations managed by local residents, non-profit organizations and companies.