Chiang Mai city and at least nine other locations in northern Thailand were plagued by toxic dust particles on Sunday as authorities were spraying water to ease the situation.
The Air Quality Index on Sunday afternoon showed poor air quality in parts of Chiang Mai, Mae Hong Son, Lamphun, Lampang, Phayao, Chiang Rai and Nan. All -- including the city of Chiang Mai -- were in the red zone, meaning PM2.5 readings were above the acceptable standard of 50 microgrammes per cubic metre.
The worst air quality was in Mae Sai district of Chiang Rai, where the index was at 467, far beyond the 'unhealthy' threshhold of 200.
PM2.5 in Mae Sai hit a level of 353 at 9am, according to latest figures released by the Pollution Control Department.
The Air Quality Index on Sunday afternoon shows numerous red spots in the northern region. (Screen capture from the Pollution Control Department)
Chaiyaphol Thitisak, the Disaster Prevention and Mitigation Department director-general, ordered trucks to spray water in hopes of reducing the heavy smog. People in the hardest-hit locations were advised to wear masks.
Weerachai Chaimongkol, the kamnan of tambon Pah Dad in Muang district of Chiang Mai, urged the government to step in to tackle the problem as it was beyond the scope of provincial authorities.
Mae Fah Luang University in Chiang Rai decided to cancel all classes on Monday and Tuesday. "The university advises all students and staff to protect yourselves and take care of your health by avoiding outdoor activities, especially outdoor sports, and wearing a mask whenever you go outdoors," it posted in a message on its Facebook page.