Delhi , India

Where the data comes from

The data featured on this page comes from WHO’s Global Platform on Air Quality and Health. This includes an urban air pollution database with monitoring data collected from 4,300 cities worldwide, representing nearly 40% of the world’s urban population. It also includes a global ambient (outdoor) air pollution database for 108 countries and every corner of the world. These data contain measurements for the annual average exposure to particulate matter, PM 2.5, the tiny particles within air pollution that can penetrate the body and are most closely linked with premature death and climate change.

In the past 2 years, the database - now covering 4,300 cities and health burden data for nearly every country in the world - has nearly doubled in size, with more cities measuring and reporting on air pollution and levels and recognizing the associated health burden.

Calibration for the air pollution gauge was completed through partners at the University of Bath to help represent levels in which the majority of cities in the database fall.