Air pollution is not only a major health risk, it also has damaging impacts on the environment and agricultural crop yields. These impacts have significant economic consequences. While existing policies have made progress in reducing air pollution, further action is needed to bring air quality to safe levels. The report uses highest quality data available and state-of-the-art modelling to identify the most effective 25 measures to reduce air pollution. It takes the region’s considerable diversity into account and splits the measures into three groups: Conventional emission controls Next-stage air-quality measures for reducing emissions leading to formation of fine particulates and are not yet major components of many clean air policies Measures contributing to development priority goals with benefits for air quality Implementing the 25 measures is projected to cost US$300–600 billion per year, only about 5 per cent of the projected annual GDP increase of US$12 trillion in 2030.