| Rank | City |
|---|
Data Source and Description
●Air quality data of mainland China, Hong Kong, Macao, and Taiwan obtained from local government agencies for ecological environment and environmental monitoring.
●Worldwide air quality data comes from aqicn, AirNow, OpenAQ and local environmental agencies.
●For the stations at mainland China, the Air Quality Index (AQI) value adopts the Chinese standards. Other stations adopt their local standards or U.S. standards.
Annual National Environmental Data and Statistics59