At the start of another hot, dry summer, air quality has plunged across the much of northern Thailand, Laos and Myanmar.

On March 15, air quality across the famed Golden Triangle, known normally for its bucolic rolling hills and paddy fields, spiked to unhealthy and in some places hazardous with PM2.5 levels exceeding 200 and in some cases even above 300.

Satellite images showed a proliferation of forest and open field crop-waste fires burning across central and northern Thailand and Laos. A dense concentration of fires was visible across Thailand’s border to the north, in Myanmar – an area racked by conflict in the country’s ongoing civil war, and out of reach of any fire control measures Thailand can muster.

Burning is a common and virtually zero-cost practice to dispose of the previous crop’s residue and assorted fallen leaves, to prepare fields for the next round of cultivation. In the dry season fires set illegally in forests to clear them for agriculture, also go out of control, contributing to the problem and raising carbon emissions.

Thailand is ranked among the ten most vulnerable countries in the world to climate change because of its extensive coastline, rural communities dependent on agriculture and heavily populated urban areas located on flood-prone plains.

As global temperatures warm, the risk of fires, as well as extreme weather events, increases; northern Thailand last year saw disastrous, debris-laden flash floods from unusually concentrated rain, its effect magnified by deforestation. This year, temperatures are forecast to be slightly lower than last year, but rainfall is predicted to be 10-20 percent higher than normal.

Additionally, Thailand’s capital Bangkok, a city of now well over 10 million people, is, like many other massive Southeast Asian cities, sinking, as its underground aquifers are drained and sea levels rise. Like Jakarta in Indonesia and Manila in the Philippines, Bangkok is built – or rather overbuilt – on marshy wetlands. Bangkok depends on hundreds of pumps to stay above water and experts say it must inevitably be moved or at least its population density must be eased by relocating large segments of its population.

Indonesia has ambitious plans that are proceeding slowly to relocate its capital to the jungles of Kalimantan for the same reason and the Philippines has for years been trying to find a way to ease the overcrowding of Metro Manila. Thailand also has plans – it hopes to pass legislation on clean air this year and is targeting carbon neutrality by 2050, and net-zero by 2065 – but it is up against considerable inertia in the system, and in society at large.

Where is the smoke coming from?

Take agriculture, for instance. There is some argument over the main drivers of the smoke that shrouds northern Thailand, but according to a report from the World Bank, agriculture contributed to approximately 18 percent of PM2.5 emissions in Thailand in 2023. PM2.5 refers to particulate matter 2.5 microns or less in diameter – which can be present in the air but virtually invisible, so even a blue sky can be deceptive.

On Sunday, March 16, Thailand’s largest northern city, Chiang Mai, a favorite of tourists and retirees, briefly became the worst city in the world in terms of air quality, surpassing even Lahore and New Delhi. This year is shaping up to be as bad as the previous summers of 2023 and 2024, when local hospitals reported being overwhelmed by patients suffering from respiratory problems.

Fines and exhortations against burning clearly only scratch the surface of a complex issue involving cultural practices, crop changes, market forces, public health – and, to a large extent, public apathy.

Activists like Weenarin Lulitanonda, co-founder of the Thailand Clean Air Network, cite the Air Quality Life Index (AQLI) of the Energy Policy Institute at the University of Chicago, which estimates that the air people breathe in Northern Thailand is cutting their lives short by 2-3 years.

In 2024, Thailand’s Ministry of Public Health estimated that 12.3 million illnesses were linked to air pollution. In January 2025, the United Nations Children’s Fund (UNICEF) said it was “deeply concerned” about escalating PM2.5 air pollution in Thailand, which was “putting the health of approximately 13.6 million children across Thailand at risk.”

According to UNICEF’s 2023 report “Over the Tipping Point,” the number of children in Thailand highly exposed to PM2.5 is greater than those affected by other climate hazards, such as floods, heat waves, and droughts.

There is, however, no real sense of urgency across the country. And people like Weenarin – who says she refuses to remain a hopeless bystander – are a relatively rare species. Across the region, activists are also generally not the favorite citizens of governments or big corporations.

Regional similarities

Laos is a one-party Communist country and Myanmar is a military regime with some border areas under the control of ethnic armies in a state of war. Thailand has more space for civil society, but even so there are limits. In Cambodia, journalists exposing environmental issues such as illegal logging, have even been killed. The situation is not much better in Indonesia and in the Philippines, journalists and activists have frequently been killed for challenging powerful interests.

Specifically in northern Thailand, the primary driver of air pollution is open burning in agricultural or forested areas. The region’s topography and climate exacerbates the problem, with smoke accumulating in valleys, and winds bringing smoke in from neighboring Laos and Myanmar. Wind patterns also routinely divert smoke from massive palm crop fires in Indonesia’s northern Sumatra to Malaysia and Singapore.

Changing crop practices have been blamed for making the problem worse in recent years. Thailand’s demand for maize for animal feed cannot be met in-country, so much of it is sourced from Laos, Cambodia, Myanmar and Vietnam. Smallholder farmers in the region enter contracts with large companies, and are under pressure to maximize output on tight deadlines. With no capital to invest in modern techniques and machinery such as harvesters, field burning is the easiest and cheapest resort.

Feeling the heat, Thailand’s largest agricultural conglomerate, Charoen Pokphand, commonly known as the CP Group (2023 revenue US$96.5 billion), on Feb. 5 reiterated that it would not buy maize – used principally as animal feed – from areas where growers burn the plant residue after the harvest. CP is active throughout Southeast Asia so its policies can also have an impact in Indonesia, Malaysia and elsewhere.

“​CP has clearly announced it will not purchase or support maize which comes from any areas where growers practice crop plant burning,”​ Jomkitti Sirikul, senior vice-president of the CP Group, said after a meeting with Agriculture and Cooperatives Minister Narumon Pinyosinwat.

Activists and experts however, remain skeptical – and demand supply chain traceability and transparency in much the same way that activists and European governments have demanded – and got – growing traceability measures imposed on the palm oil business in Malaysia and Indonesia due to similar problems with fires for crop clearing, especially in Indonesia.

Meanwhile on the ground, a plethora of local initiatives from offroad motorcycle clubs to crop diversification, have taken root in Thailand.

Yet, studies show that, not just in Thailand but across the region, the health hazards of burning are poorly understood, and community awareness and involvement is inadequate. The link to climate change is also poorly understood.

A climate awareness survey across the region conducted by the Singapore-based ISEAS – Yusof Ishak Institute in 2023, found that the vast majority (86.9 per cent) of Southeast Asians saw tackling climate change as the responsibility of national governments, followed by business and industry (61.8 per cent) and individuals (45.9 per cent).

“Few respondents are involved in active advocacy; the region has a long way to go” wrote ISEAS-Yusof Ishak Institute researcher Melinda Martinus.

Most Southeast Asians are pessimistic about their governments and do not think individual roles count for much in the grand scheme of things, she wrote.

Evidence from successful clean air movements has shown that a groundswell of collective public opinion may drive the political will needed to win the war against air pollution, says Thailand’s Weenarin. “Thai citizens of all walks of life need to be intrinsically aware and collectively demand that the government uphold its duty to respect and protect our right to breathe clean air,” she says.