Air pollution across the upper North remains at critical levels with authorities monitoring almost 400 active hotspots in Chiang Mai alone on Sunday.
Government spokeswoman Narumon Pinyosinwat said fires have undoubtedly affected air quality, with 17 provinces in the North reporting an increase in levels of hazardous, ultra-fine PM2.5 pollutants on Sunday.
Only Nakhon Sawan and Uthai Thani reported PM2.5 readings below the Pollution Control Department’s “safe” threshold, set at 50 microgrammes per cubic metre (μg/m³).
Chiang Dao district in Chiang Mai reported the highest PM2.5 reading in the North on Sunday at 360μg/m³.
Ms Narumon said the worsening pollution is caused by a combination of factors which include arson, drought and prevailing wind patterns which trap pollutants right above Thailand.
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