Every dry season, the same grim pattern returns to parts of Southeast Asia. Satellite images show hotspots spreading across Sumatra and Indonesian Borneo. Smoke drifts over villages, cities, and eventually national borders. Schools close, flights are delayed, and people line up at clinics with coughs and stinging eyes. Indonesia's wildfires are not a one-off disaster but a recurring crisis, and understanding why they happen — and why they resist even enormous firefighting efforts — helps explain why the problem has proved so stubborn.
A Fire Problem Rooted in the Land
Indonesia is home to some of the world's largest tropical peatlands, particularly in Sumatra, Kalimantan, and parts of Papua. Peat is essentially layers of partially decayed vegetation that have accumulated in waterlogged ground over thousands of years. In its natural state, peatland is wet and fire-resistant. The trouble begins when the land is drained.
Since the 1990s, large areas of peat swamp forest have been cleared and drained for oil palm plantations, pulpwood estates, and smallholder farmland. Canals are cut to lower the water table so crops can grow. Once drained, peat turns from a soggy carbon sponge into something closer to fuel. Dry peat burns slowly and deeply, and unlike ordinary forest fires that race through leaves and branches, peat fires smolder underground. They can keep burning beneath the surface for weeks or months, popping up in new places, producing far more smoke per hectare than surface fires, and flaring up again long after the flames above ground appear to be out.
Fire as a Cheap Land-Clearing Tool
A second piece of the puzzle is human behavior. Burning is the cheapest and fastest way to clear vegetation. For smallholder farmers, lighting a fire before planting season has long been traditional practice. For some plantation companies and their suppliers, it has been a way to convert forest and scrubland into productive land quickly — even though Indonesian law prohibits clearing land by burning and companies have faced prosecutions when fires start on their concessions.
Enforcement is difficult across vast, remote landscapes with overlapping land claims. When fires ignite on plantation land, responsibility is often disputed. Small farmers may say they burned only a few hectares, while fires escape into drained peat and spread far beyond what anyone intended. This mix of legal gray zones, economic pressure, and weak on-the-ground capacity is a major reason the fires return season after season.
When Drought Turns Sparks into Disasters
Indonesia has two fire seasons in a normal year, but the scale of burning depends heavily on the weather. During El Niño years, and when the Indian Ocean Dipole — a temperature pattern in the ocean west of Sumatra — is in its positive phase, the dry season becomes longer and more severe. The wet peat that might normally dampen a fire dries out.
Some years illustrate the pattern clearly. In 1997, fires linked to an intense El Niño burned enormous areas and produced a haze episode that affected much of Southeast Asia. In 2015, an El Niño year, estimates put the burned area at roughly 2.6 million hectares, and the World Bank estimated economic losses of around 16 billion dollars. In 2019, when a strong positive Indian Ocean Dipole coincided with drought, hundreds of thousands of hectares burned again and haze blanketed parts of Indonesia, Malaysia, and Singapore. In 2023, El Niño conditions once more pushed fire activity upward. The lesson is consistent: the underlying conditions for fire exist every year, but drought years turn them into regional emergencies.
The Haze Problem
What makes Indonesia's wildfires an international issue is smoke rather than flame. Burning peat releases thick smoke laden with fine particulate matter, known as PM2.5, particles small enough to lodge deep in the lungs. When winds blow the smoke toward populated areas, air quality can deteriorate to hazardous levels for days or weeks at a time.
The health consequences are significant. During the 2015 episode, Indonesian authorities reported hundreds of thousands of cases of respiratory infection, and one widely cited study estimated tens of thousands of premature deaths across Indonesia and neighboring countries, driven largely by the smoke. People with asthma, children, and the elderly are hit hardest. Beyond health, thick haze disrupts daily life: schools suspend classes, outdoor work becomes dangerous, visibility drops to a few hundred meters, and airlines cancel or delay flights.
Because the smoke crosses borders, the issue has long strained Indonesia's relations with Singapore and Malaysia. A regional haze agreement under ASEAN has been in place for years, and Indonesia ratified it in 2014, but cooperation on prevention and accountability remains a work in progress.
The Environmental Cost
The damage is not limited to the air. Peatland fires release enormous amounts of stored carbon, making Indonesia's fire seasons a notable contributor to global emissions — some episodes have rivalled the annual emissions of industrialized countries. The fires also destroy habitat for endangered wildlife. In Borneo and Sumatra, orangutans, sun bears, and countless other species lose forest to fire and to the land conversion that makes fire more likely. In severe years, rescue teams have taken in orangutans weakened by smoke or driven out of burned habitat.
There is a longer-term loss as well. Peat that has burned can take centuries to re-form. Once the land is scorched and drained, it is more prone to flooding in the wet season, more vulnerable to future fires, and often converted to monoculture plantations — a cycle that is difficult to reverse.
What Indonesia Has Been Doing About It
The response has grown steadily more serious, especially after the 2015 crisis. Key efforts include:
- Rewetting peatlands. Indonesia established a peatland restoration agency in 2016 with the goal of restoring millions of hectares of degraded peat. One of its main techniques is blocking drainage canals so water returns to the peat, which makes the land less flammable.
- Moratoria on land conversion. Presidential decrees have restricted new permits for oil palm plantations and for converting primary forest and peatland, though critics note gaps in enforcement.
- Fire brigades and monitoring. The forestry ministry maintains dedicated firefighting units, and satellite-based systems track hotspots in near real time so crews can respond faster. Local weather-modification teams have also been deployed in severe years to induce rain over fire zones.
- Community fire care groups. Villages in fire-prone areas have organized local teams to patrol, report hotspots, and promote land preparation without burning.
- Legal action. Companies whose concessions burn have faced civil and criminal suits, and some large palm oil firms now enforce zero-burning policies across their supply chains.
Progress is real but incomplete. Peat restoration is slow and expensive, budgets fluctuate, and land tenure conflicts persist. The recurring lesson of the past decade is that firefighting alone cannot solve the problem; prevention through keeping peat wet and changing how land is cleared matters far more.
What Residents and Travelers Should Know
If you live in or plan to visit fire-prone regions — Riau, Jambi, South Sumatra, Central Kalimantan, West Kalimantan, or parts of Papua — a few practical steps make a difference during haze season, which typically runs from around July to October.
Check air quality daily using an app or website that reports PM2.5 readings rather than relying on how the sky looks, since haze can be significant even when visibility seems acceptable. When pollution is high, stay indoors with windows closed if possible, and use an air purifier if you have one. Ordinary cloth masks are not very effective against fine particles; an N95 or KN95 respirator fits more snugly and filters PM2.5 far better. Drink water, avoid outdoor exercise during heavy haze, and take children, elderly relatives, or anyone with respiratory or heart conditions especially seriously.
Travelers should be aware that haze season can bring flight delays and cancellations at airports in affected provinces, and outdoor attractions such as national parks may be less enjoyable or temporarily closed. Checking conditions shortly before departure and building some flexibility into plans is wise.
Questions People Often Ask
Are the fires natural? Wildfires do occur naturally in some ecosystems, but the vast majority of Indonesia's fires are human-caused, sparked by land clearing or escaping into drained peat that would not normally burn.
When is the risk highest? The main burning season falls in the Southern Hemisphere dry season, roughly July through October, and the worst years coincide with El Niño or a strong positive Indian Ocean Dipole.
Will the fires ever stop completely? Complete elimination is unlikely as long as millions of hectares of drained, degraded peat remain and burning stays the cheapest way to clear land. But the fires are not inevitable. Years with strong prevention, early detection, and wetter weather have shown that the scale of burning can be dramatically reduced.
A Problem With a Known Solution
Perhaps the most important thing to understand about Indonesia's wildfires is that the underlying causes are well understood. Drained peat burns. Burning is cheap and rarely punished. Drought years multiply the damage. The solutions — rewetting peatlands, enforcing zero-burning rules, supporting farmers with alternatives, and investing in early response — are equally well understood. The gap between knowledge and implementation is where the real challenge lies. Each severe haze season draws fresh attention and fresh commitments; whether the cycle weakens over time depends on how long that attention lasts once the smoke clears.