Chiang Mai led other cities as the most polluted place in the world on Tuesday morning, as thick smog continued to plague the northern region.
Chiang Mai municipality regained its spot as the most polluted city at 9.20am, with fine dust levels recorded at 203 microgrammes per cubic metre, according to IQAir rankings. The weather monitoring website labelled the city "very unhealthy", and it could continue into Wednesday and beyond.
Thailand will celebrate the Songkran water festival from Thursday until next Monday, and Chiang Mai city is normally one of the most popular destinations for holidaymakers.
Chiang Mai governor Nirat Pongsitthithavorn on Monday declared disaster zones in seven districts but not in Muang district, which is one of the most polluted areas in the province. The declaration facilitates the provision of budget-tied emergency assistance to Fang, Phrao, Chiang Dao, Mae Taeng, Chaiprakarn, Mae Ai and Wieng Haeng districts.
The governor ordered state officials to work from home until Thursday, because of the air pollution, and advised residents and visitors to abstain from outdoor activities if possible, and wear a mask if they leave home.
At Monday's press conference, Mr Nirat was asked why he deliberately played down the pollution levels in Chiang Mai and the number of patients with respiratory problems. He strongly denied this. Officials "have given the press all information and you can freely write about it", he said.
Pita Limjaroenrat, chief adviser of the Move Forward Party, on Monday also said the governor and provincial officials were being selective in their decisions. "Other districts with serious pollution are not on the list," he posted on the X platform.
The northern provinces of Lamphun, Lampang, Phayao, Nan, Chiang Mai and Mae Hong Song were also on the list of areas with high PM2.5 dust levels on Tuesday, but their situation was not as dire as Chiang Mai's, according to the Pollution Control Department.
With concern about high air pollution levels growing ahead of Songkran, weather forecasters on Tuesday issued an alert, warning of possible summer storms in the northern, northeastern and central regions until Thursday. Chiang Mai could expect scattered storms on Wednesday and Thursday, the Meteorological Department said.
Chiang Mai takes the lead as the world's most polluted city on Tuesday, amidst ongoing air pollution plaguing the province and other areas in the northern region. (Screenshot from IQAir)