Indonesian wildfire haze puts 3.4 million at risk as peat burns on Sumatra and Borneo

Indonesia’s health ministry said on Wednesday that 3.4 million people in seven provinces on Sumatra and Borneo face a raised risk of respiratory infection from wildfire haze, as El Niño-driven peat and forest fires continue to burn. Schools have closed in parts of Riau and Jambi. Smoke has reached Malaysia and Singapore. President Prabowo Subianto said on Tuesday that the government had sent helicopters, aircraft, water pumps and thousands of personnel against the blazes.

Fires between January and July scorched more than 200,000 hectares, an area the government compared to three times the size of Jakarta. The ministry lists 87 districts and cities in Jambi, Riau, South Sumatra, West Kalimantan, Central Kalimantan, South Kalimantan and East Kalimantan. About three million people in 37 of those districts were already counted as directly exposed in figures released late last week. Health Minister Budi Gunadi Sadikin urged residents to wear masks and to check official air-quality apps before going outside.

In Pekanbaru, the Riau capital, visibility has fallen to around 500 metres. PM2.5 readings have reached 235.7 micrograms per cubic metre, more than 15 times the World Health Organization’s 24-hour guideline of 15 micrograms. Abdullah, a 38-year-old business owner in the city, told AFP the smog thickens at night and that “Pekanbaru almost like a dead city. A lot of people don’t dare go out. And if they do, they wear masks.” Jambi ordered home schooling for kindergarten and primary pupils for the rest of the week. The ministry said it had distributed more than 260,000 masks.

Hospitals are already counting the surge

West Kalimantan health facilities have recorded about 5,000 emergency visits for respiratory infections each week since July, ten times the weekly average of about 500 in the first half of the year. Central Kalimantan has logged about 70,400 acute respiratory infection cases this year, with a sharp rise since July. Nationally, weekly respiratory cases have run around 400,000 since late July and had passed 10.6 million for the year by early August. Agus Jamaludin, head of the ministry’s Health Crisis Center, said 314 extra health workers had been sent, with priority on Central and South Kalimantan.

PM2.5 particles are small enough to reach deep into the lungs. Sadikin said they can irritate eyes and throats, tighten breathing and worsen asthma and other chronic lung disease. Children, pregnant people, older residents and anyone with existing lung conditions sit at the top of the risk list. The ministry’s 3.4 million figure is an exposure estimate, not a patient count. The hospital numbers are the part of that exposure that has already arrived at a clinic door.

Why peat fires are hard to put out

Much of the fuel is drained peat. Once alight, it burns below the surface and can smoulder for weeks. Helicopters and water bombers help on the canopy. They do not easily reach fire that is travelling through dry peat several metres down. El Niño has lengthened the dry season and lowered water tables. Land that was cleared for pulp and oil palm dries faster than intact swamp forest. That pattern is not new. The 2015 and 2019 seasons produced regional haze events that closed airports and sent patients across the Malacca Strait.

Prabowo’s deployment of aircraft and thousands of personnel is the standard national response. Local governments add school closures and mask distributions. Neither tool restores the water that peat needs if the rains stay late. Cross-border complaints from Malaysia and Singapore will follow if the plume thickens. ASEAN has a haze agreement. It has not stopped a dry-season burn when the ground is ready to ignite.

For residents of Pekanbaru and Palangka Raya the immediate choices are smaller. Stay inside. Wear a mask. Watch the index. Keep children home if the district office says so. The 235 microgram reading in Riau is the number that makes those choices feel less optional. The fires that produced it are still burning.