This 2021 World Air Quality Report presents an overview of the state of global air quality in 2021. The report is based on PM2.5 air quality data from 6,475 cities in 117 countries, regions and territories around the world. The PM2.5 data presented here is reported in units of micrograms per cubic meter (μg/m3) and utilizes the latest World Health Organization (WHO) annual PM2.5 air quality guideline and interim targets as a framework for data visualization. Of the air quality monitoring stations included in this report, 44 percent were operated by governmental agencies, while the remainder represent monitoring stations managed by citizen scientists, non-profit organizations and companies.

Read the report here