CHIANG RAI – The Supreme Administrative Court has directed the National Environment Board to officially designate Chiang Rai, Chiang Mai, Lamphun and Mae Hong Son as PM2.5 pollution control areas each year from February to May.
The court’s decision, handed down on 1 August, requires the Board to act under Thailand’s National Environmental Quality Promotion and Preservation Act 1992. The Board must publish the official declaration within ninety days of the ruling.
The court case began after Mr. Phumi Watcharajaroenphitpol, a resident of Ban Pong Subdistrict in Chiang Mai, filed a lawsuit.
He argued that the National Environment Board failed to address persistent hazardous smoke from forest fires in the North, which caused PM2.5 dust levels far above legal limits. The thick haze threatened the health and well-being of thousands across the region.
In its ruling, the court acknowledged that the Board was aware of the PM2.5 dust issue and had launched pollution control plans in response. Despite several government agencies working together since 2018, air quality in Chiang Mai, Chiang Rai, Lamphun and Mae Hong Son from February to May still regularly exceeded safe levels.
The court noted health data showing sharp rises in heart and lung disease, respiratory problems, eye infections and skin conditions during the worst haze periods. The ongoing high pollution made it clear that these provinces met the legal definition of areas with severe pollution problems that are dangerous to public health.
The Board’s failure to declare these provinces as pollution control zones was ruled a neglect of their legal responsibilities.
The court also considered the balance between public health and economic interests, including image, investment and tourism in these provinces. Ultimately, it ruled that people’s health comes first.
The Board must formally designate these four provinces as pollution control areas for the months when PM2.5 peaks beyond safe limits. If later actions by government agencies succeed in reducing pollution below the legal threshold, the Board may consider lifting the designation.
The court amended an earlier ruling and ordered the National Environment Board to announce in the Royal Gazette that Chiang Mai, Chiang Rai, Lamphun and Mae Hong Son are officially PM2.5 control zones from February to May every year.
The Board has ninety days from the date of the final court decision to complete this declaration.
