Thailand’s leader traveled to the northern city of Chiang Mai earlier this week to personally inspect areas with extremely poor air quality. Prime Minister Prayuth Chan-ocha ordered government agencies to take urgent measures to fight the air pollution, which has reached dangerous levels. Recently, pollution levels in and around Chiang Mai have risen above those of major world cities known for having poor air quality. In recent days, tests found that Northern Thailand had very high levels of airborne particulates known as PM2.5. PM2.5 particulates are small enough to be taken into the lungs and enter the bloodstream. They can cause breathing problems and may raise the risks of heart disease and even some cancers. Recently, the Chiang Mai area has had PM2.5 measurements as high as 480 micrograms. This is more than six times higher than Thailand’s air pollution safety limits.