BBC/Wasawat LukharangSome families are considering moving out of Chiang Mai because of its chronic air pollution Tirayut Wongsantisuk and his wife moved to Chiang Mai in the 2010s, drawn by the hilly region's cool air and lush greenery.
But worsening air quality in the Thai city, especially during this time of the year, have prompted them to consider relocating for the sake of their children.
Two of their daughters have experienced frequent nosebleeds. "I've been thinking, maybe we really should move during this time... because if something bad happens to our child, we'll feel terrible forever," Tirayut , 41, told the BBC.
Smoke from raging fires have choked parts of northern Thailand this past week, with Chiang Mai ranking among the world's most polluted cities, according to monitoring group IQAir.
A thick blanket of haze hovered over the horizon when BBC Thai visited Tirayut and other families in Chiang Mai, covering what once were mountainous views. There was a persistent burning smell in the air.
Satellite data showed a record number of 4,750 hotspots across Thailand on Tuesday, mostly in forested areas.
As of Wednesday morning, Chiang Mai's PM2.5 level, which refers to the concentration of tiny, hazardous particles smaller than 2.5 micrometres, was classified as "very unhealthy".
The months of November to March mark peak fire season in the region as farmers burn off fields before new seeds are sown. In addition to these are wildfires that break out naturally because of dry conditions in forests and farmlands.
BBC/Wasawat LukharangTirayut (second from left) says his oldest daughter, six, has experienced nosebleeds and developed rashesPhotographs on local media show mountains engulfed by flames, with some residents likening the blazes to "volcanoes erupting", according to local news outlet Khaosod.
Earlier this week, authorities ordered the closure of parks with high fire risk and warned that anyone found entering those areas to start fires would be arrested immediately.
In Thailand, those convicted of illegal forest burning face up to 20 years in prison and a 2m baht ($61,100; £46,200) fine.
Exposure to haze can cause various health issues, from itchy eyes and nose bleeds to heart attacks.
Tirayut says his oldest daughter, six, "had nosebleeds, a rash, and an allergic reaction in her eyes, to the point where her eyelids were swollen".
Benjamas Jaiparkan has sent her children to the neighbouring Phayao province, where the air quality is better, to temporarily live with relatives. But the 35-year-old is thinking of leaving Chiang Mai permanently.
Benjamas, a public school teacher, is especially worried about her four-year-old son, who started getting nosebleeds last year.
"I feel so sorry for him because I don't know how much more his lungs can take," she said.
Over the years, activists and residents in Thailand have filed lawsuits to demand government action against pollution.
In July 2023, about 1,700 people in Chiang Mai brought a case against former Prime Minister Prayut Chan-o-cha and two state agencies for failing to exercise their authority to reduce pollution in the north, which they say was shortening each of their lives by about five years.
In January 2024, a Chiang Mai court ordered the government to come up with an emergency plan to improve air quality within 90 days.
Hazardous haze has also been choking people elsewhere in South East Asia, with the most number of hotspots flaring up across Malaysia and Indonesia in seven years.
