Virtually all (99.9 percent) of Southeast Asia’s 656.1 million people live in areas where particulate pollution exceeds the World Health Organization (WHO) guideline of 5 μg/m³. Despite the lockdowns of the pandemic, pollution continued to rise in much of Southeast Asia in 2020. This pollution cuts short the life expectancy of the average Southeast Asian person by 1.5 years, relative to what it would be if the WHO guideline was met. That’s a total of 959.8 million person-years lost to pollution in the eleven countries that make up this region. Some countries in the region experience greater impacts from pollution.