Fine dust reached hazardous levels in many northern and northeastern provinces in the 24 hours to 9am Thursday, with PM2.5 readings at 64-199 microgrammes per cubic metre of air - and the worst pollution in Chiang Rai.
The Pollution Control Department reported on Thursday that the level of particulate matter 2.5 micrometres or less in diameter reached 199 μm/m³ in tambon Wiang Phang Kham of Mae Sai district in Chiang Rai. The air quality index there reached the hazardous level of 309, the highest in the country.
In the North, unhealthily high smog levels were also reported in Muang and Mae Chaem districts of Chiang Mai, Muang district of Lamphun, Mae Mo and Muang districts of Lampang, Muang district of Phrae, Muang and Chalerm Prakiat districts of Nan, Muang district of Phayao, Muang district of Mae Hong Son and Mae Sot district of Tak.
In the Northeast, similar conditions were reported in Muang district of Loei and Muang district of Khon Kaen.
In the Central Plains, unhealthy levels of PM2.5 were recorded in Chalerm Prakiat district of Saraburi, Muang district of Nakhon Sawan, Phra Nakhon Si Ayutthaya district of Ayutthaya and Muang district of Kanchanaburi.
Deputy Prime Minister Prawit Wongsuwon visited the northern province of Chiang Mai on Thursday to see the situation in the North at first hand.
He blamed the air pollution on forest fires and said local officials were trying their best to put out the fires and were trying to convince people not to burn-off. The key to the problem was getting the people's cooperation.