
Hazardous levels of PM2.5 remained only in the upper North at noon on Sunday, with the worst air pollution in Chiang Dao district of Chiang Mai province.
The Pollution Control Department reported that hazardous levels of particulate matter 2.5 micrometre and less in diameter (PM2.5) were detected in Chiang Mai, Chiang Rai, Lampang, Lamphum, Mae Hong Son, Nan and Phayao provinces.