Smoke from fires across Indonesia is spreading across Southeast Asia, pushing air pollution to hazardous levels and highlighting ongoing challenges in land management, regional cooperation and climate resilience.
A widening Indonesia wildfire crisis is sending haze across Southeast Asia, degrading air quality from Malaysia and Singapore to the Philippines and demonstrating how domestic land and fire-management challenges can quickly become regional public-health and economic concerns.
Malaysia declared an emergency on Friday in Serian, Sarawak, after its Air Pollutant Index rose above 500, the threshold for emergency conditions. Schools have closed in affected areas, while authorities have begun cloud-seeding operations in an effort to encourage rainfall.
Singapore’s 24-hour Pollutant Standards Index also entered the “unhealthy” range on Friday for the first time because of haze since October 2023. Smoke has traveled as far as the Philippines, while in Indonesia approximately 1.4 million students across six provinces have shifted to remote learning because of deteriorating air quality.
The episode illustrates a longstanding regional challenge: fires within one country can produce environmental, health and economic effects far beyond its borders.
Indonesia wildfire season intensifies
Indonesia is confronting a severe fire season as an unusually strong El Niño contributes to hotter and drier conditions.
Forestry Ministry data show that 202,004 hectares burned between January and July, already exceeding comparable levels in 2019 and 2023, although remaining well below the scale recorded during the catastrophic 2015 fire season. Nearly 95,000 hectares burned in July alone.
Climate conditions are intensifying a problem that Indonesian officials say is also heavily influenced by human activity. Authorities are investigating land clearing and other potential ignition sources while inspecting 19 companies where fires were identified within concession areas covering more than 11,000 hectares.
The climate impact is also mounting. The European Union’s Copernicus monitoring service estimated that Indonesian fires emitted 17.1 million metric tons of carbon over a recent seven-day period, 429% above the seasonal mean.
September could prove critical. Forestry Minister Raja Juli Antoni has warned that El Niño is expected to peak during the month, describing it as a major test for efforts to contain the fires.
Why peatlands matter
One of Indonesia’s central vulnerabilities is its vast peatland landscape.
Healthy tropical peatlands are waterlogged ecosystems capable of storing enormous quantities of carbon. Once drained or degraded, however, they become far more susceptible to fire. Peat fires can smolder beneath the surface for extended periods, making them difficult to extinguish while releasing greenhouse gases and particulate pollution.
Recent peer-reviewed research has found that peatland rewetting and canal blocking can reduce fire occurrence in restored areas.
Environmental groups have also raised concerns about emerging fires in South Papua, linking them to peatland degradation and land conversion associated with agricultural and energy development. Those assessments have renewed attention to how shifts in land use may shape future fire risk.
From environmental crisis to public-health threat
The most immediate regional consequence is deteriorating air quality.
Fine particulate matter, particularly PM2.5, can penetrate deep into the lungs and enter the bloodstream. The World Health Organization warns that wildfire smoke can increase respiratory and cardiovascular risks, drive hospital admissions and travel thousands of kilometers from its source.
Children, older adults, pregnant women and people with existing heart or lung conditions face particular risks.
Those health effects are already translating into wider disruption. Schools have closed or moved online, governments are issuing health warnings, and affected communities are reporting increases in respiratory illness.
The broader economic consequences can also become substantial.
The warning from 2015
The 2025 Indonesia wildfire crisis illustrates how quickly a haze emergency can expand beyond an environmental problem.
Approximately 2.6 million hectares burned that year. The World Bank estimated the cost to Indonesia at at least $16.1 billion, equivalent to 1.9% of GDP.
Transportation, trade, tourism, manufacturing and agriculture all suffered losses. More than 500,000 cases of acute respiratory infection were recorded, while the estimate did not fully capture longer-term health costs or economic losses elsewhere in the region.
The comparison provides important context for the current fire season. Severe haze can disrupt economic activity well beyond the areas where fires originate, turning land-management failures into broader regional risks.
A new dimension near Nusantara
Those risks are also becoming relevant to Indonesia’s long-term infrastructure ambitions.
Approximately 400 hectares have burned in areas around Nusantara, Indonesia’s planned new capital in East Kalimantan, including about 300 hectares in Bukit Suharto forest park, roughly 50 kilometers from the city center.
Authorities have sought additional cloud seeding and aerial water bombing to contain the fires.
Nusantara is one of Indonesia’s largest infrastructure projects, and the fires in its surrounding region highlight the need to incorporate changing environmental conditions into long-term development and land-use planning.
The issue therefore extends beyond emergency response. It also raises questions about how governments plan major investments in landscapes that may face increasing climate and ecological pressure.
ASEAN faces a familiar test
For Southeast Asia, the return of transboundary haze is also drawing renewed attention to regional cooperation.
ASEAN governments have spent decades developing mechanisms to address cross-border haze, including the ASEAN Agreement on Transboundary Haze Pollution. Indonesia has also strengthened peatland restoration, enforcement and firefighting capacity since the 2015 crisis.
Those measures contributed to several comparatively less severe fire seasons. The current episode, however, underscores the continuing difficulty of preventing fires before they become large enough to affect neighboring countries.
Longer-term prevention efforts across the region have increasingly focused on peatland protection and restoration, land-use governance, enforcement against illegal burning, corporate accountability and improved monitoring and early-warning systems.
The climate backdrop adds urgency. WHO, citing FAO and IPCC assessments, says extreme wildfires globally could become up to 50% more frequent by the end of the century as changing temperatures and rainfall patterns alter fire conditions.
A regional resilience problem
The current Indonesia wildfire remains far below the scale of 2015. But their regional reach is already significant.
Smoke has crossed several national borders. Millions of students have had their education disrupted. Governments have activated emergency measures. Companies are under investigation. Carbon emissions have risen sharply, and fires are affecting areas near Indonesia’s planned new capital.
The larger question is whether existing national and regional prevention measures will be sufficient if periods of extreme fire weather become more frequent.
For Southeast Asia, this year’s haze is therefore more than another seasonal environmental episode. It is an emerging test of how effectively governments can combine land management, public-health preparedness and regional cooperation as wildfire risks evolve.
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