CHIANG MAI – Once again, the Northern Capital city of Thailand, Chiang Mai, has landed at the top of the world’s worst air quality rankings, with AQI readings climbing deep into the “very unhealthy” range and higher.
A dense layer of smoke now covers much of northern Thailand as fires burn through forests and farmland. As a result, both residents and tourists are finding it hard to breathe, and health officials say the problem may last at least another week.
This is not an isolated case. Every dry season, smoke from seasonal fires turns the sky gray and drives PM2.5 pollution to unsafe levels. Still, this year feels harsher than usual. In March 2026, Chiang Mai repeatedly appeared near the top of global air pollution charts.
The main cause is fire. Officials say repeated burning, both illegal and uncontrolled, continues to drive the crisis. Some people burn land to prepare fields, collect forest goods, or support other unlawful activity. At the same time, dry weather, gusty winds, and temperature inversions trap smoke in mountain basins and valleys.
Across Chiang Mai province, fire hotspots have spread through several areas, especially in southern districts and around well-known mountain zones. Chiang Rai faces the same pressure, with smoke crossing borders and mixing with local fires. Because of that, PM2.5 levels often rise far above safe standards, making time outdoors a real health risk.
One of the most watched fire zones is on Doi Pha Ngom in Pa Ngio subdistrict, Wiang Pa Pao district, Chiang Rai. Fire has moved across steep slopes there, making the job harder for crews on the ground. At the same time, similar blazes are active in other parts of Chiang Rai and in forest areas across Chiang Mai, feeding the wider smoke blanket hanging over the region.
Officials Expand Firefighting Efforts on the Ground and in the Air
Authorities have stepped up their response in the worst-hit provinces. Ground teams are working long hours to put out flames, build firebreaks, and control areas they can reach safely.
Meanwhile, aircraft are helping in places that are too remote or dangerous for crews on foot. Helicopters and fixed-wing planes have been dropping water and fire retardant on active wildfire zones, including areas near Doi Pha Ngom and other mountain ridges in Chiang Rai and Chiang Mai.
In addition, the government has increased patrols to find arson suspects and enforce burning bans, although that remains difficult in large forest areas.
Even with those efforts, the outlook is still poor. Experts say air quality will likely remain dangerous for at least another week. Without steady rain, fresh fires can start quickly, and the smoke already in the air will continue to build. Because of that, people in the region should expect unhealthy conditions through early April.
PM2.5 is made up of fine particles smaller than 2.5 micrometers, about 30 times thinner than a human hair. These particles come from burning crops, wood, and other plant matter. Since they are so small, they can travel deep into the lungs and even enter the bloodstream.
In the short term, exposure can lead to coughing, throat irritation, red eyes, and trouble breathing. Over time, or during periods of heavy exposure, PM2.5 can raise the risk of asthma attacks, heart problems, lung disease, and shorter life expectancy. Children, older adults, pregnant women, and people with heart or breathing conditions face the greatest danger.
During the haze season in northern Thailand, hospitals often see more patients with breathing issues. In some cases, schools close or move classes online when pollution levels become too high.
How to Reduce Your Exposure to PM2.5
You can still take practical steps to lower your risk and protect your household. Health experts recommend the following:
- Stay indoors when possible. Try to avoid long periods outside, especially in the afternoon and evening, when the smoke often gets worse.
- Wear a proper mask outside. N95 and KN95 masks offer better protection against PM2.5 than cloth or regular surgical masks. A tight fit matters.
- Keep windows and doors shut. Use air conditioning or fans on recirculate mode so outside air does not flow in.
- Use an air purifier indoors. HEPA-filter models work best for trapping fine dust. Put them in bedrooms and common rooms.
- Check the air quality every day. Follow updates from apps like IQAir, Air4Thai, or local monitoring stations before going outside.
- Avoid outdoor workouts. Skip running, cycling, and other heavy activities when pollution is high. Exercise indoors instead.
- Pay attention to warning signs. Get medical care right away if you feel chest pain, dizziness, nausea, or severe breathing trouble, especially if you already have health issues.
For people in high-risk groups, doctors also advise keeping extra medicine on hand and avoiding any unnecessary trips. Even healthy adults should limit exposure until the air improves.
Daily Life Under the Smoke in Chiang Mai and Chiang Rai
Many people in Chiang Mai say the sky now looks dark and dull from the moment they wake up. Visitors who planned to explore temples or hike in the mountains are instead staying in cafes, shopping centers, and other indoor spaces with air conditioning. At the same time, farmers are worried about the effect of smoke on crops and animals.
In Chiang Rai, people living near Doi Pha Ngom and other fire areas report a constant smell of burning wood. Schools have told students to wear masks during outdoor breaks, and some local events have already been delayed or canceled.
Businesses are feeling the effects, too. Outdoor tourist sites are seeing fewer guests, while demand for masks and air purifiers has jumped. Even so, local communities continue to help each other. Some neighbors share purifiers, and volunteer groups assist with fire checks, sometimes using drones.
This yearly air pollution crisis will not disappear on its own. Many specialists say northern Thailand needs better options than slash-and-burn farming. That could include training for farmers, support for cleaner land-clearing methods, and stronger action against illegal burning and arson.
At the same time, reforestation projects, public education, and closer cooperation with nearby countries could help lower the number of hotspots over time. Some years, early rain helps clear the air. Still, the weather alone cannot solve the problem.
For now, the top priorities are clear: stop the fires, protect public health, and help people stay safe indoors.
If you’re in Chiang Mai, Chiang Rai, or nearby provinces, treat this smoke like a major weather emergency. Check air quality reports several times a day, turn your home into a cleaner indoor space, and avoid taking risks with your lungs.
The haze will pass, but until it does, smart daily choices can protect your health and your family. Stay updated, wear a mask when needed, and stay inside when the AQI climbs into the red. Northern Thailand is worth protecting, and so is your ability to breathe.
