PM2.5 air pollution was behind approximately 160,000 deaths in the world’s five most populous cities in 2020, according to a Greenpeace Southeast Asia analysis of IQAir data from a live Cost Estimator. While some cities saw small improvements in air quality as a result of COVID-19 lockdowns, the devastating impact of air pollution underscores the need to rapidly scale up clean energy, build electrified, accessible transport systems and end reliance on fossil fuels.