Toxic Haze from Indonesian Wildfires Spreads Across Malaysian Borneo

VoS NEWS DESK | INTERNATIONAL | 1 September 2026

Malaysia's Sarawak state is experiencing its worst haze episode in years as smoke from fires in Indonesia's Kalimantan and Sumatra regions continues to drift across national borders.

On Tuesday, six areas in Sarawak recorded hazardous air-quality readings above 300 on Malaysia's Air Pollutant Index. Kuching recorded a reading of 407, while Serian, close to the Kalimantan border, reached 408.

The worsening conditions have already affected education and public life. Nearly 600 schools in and around Kuching were closed on 20 and 21 August, affecting approximately 200,000 students. A further 30 schools in Sarawak were closed on 28 August, keeping more than 4,000 children at home.

Malaysia's Ministry of Health has also reported a sharp rise in respiratory-related illnesses. Asthma cases increased from 219 to 1,811 during the week of 23–29 August, while reported conjunctivitis cases rose from 146 to 720.

The crisis has not been confined to Malaysia. Smoke from Indonesian fires has spread across Brunei and Singapore, while parts of Peninsular Malaysia have also experienced deteriorating air quality. ASEAN has activated its highest Level 3 transboundary haze alert for the southern part of the region.

The fires inside Indonesia are considerably larger. Government figures indicate that more than 200,000 hectares were burned between January and July, with almost 95,000 hectares destroyed in July alone. Fire activity has continued to intensify in parts of Kalimantan.

Indonesia has deployed thousands of personnel and firefighting aircraft, while cloud-seeding operations are also being used in an attempt to encourage rainfall and suppress the fires. Authorities are investigating companies operating in areas affected by the blazes, with 19 companies currently under investigation over fires affecting more than 11,000 hectares.

Scientists say the developing El Niño pattern is worsening the conditions by producing hotter and drier weather across Southeast Asia. Peatlands are particularly difficult to control because fires can continue burning underground and reignite after appearing to have been extinguished.

The environmental consequences are also significant. Reuters reports that carbon emissions from Indonesian fires reached 17.1 million metric tonnes in a single week, approximately 429% above the seasonal average, according to Copernicus monitoring data.

Malaysia is now considering additional measures. Sarawak officials have indicated that cloud-seeding operations could begin in early September if weather conditions permit, as authorities attempt to bring temporary relief to areas suffering from persistent haze.

VoS STRATEGIC INSIGHT

The Indonesian wildfire crisis is becoming more than a domestic environmental emergency. The movement of smoke across national borders demonstrates how extreme weather, land-use practices and climate conditions can rapidly become a regional public-health and economic problem.

The combination of dry conditions, peatland fires and transboundary smoke could keep the crisis active for weeks. Experts have warned that the situation may remain difficult until substantial rainfall arrives, potentially towards the end of September or into October.

For Malaysia and neighbouring countries, the immediate priorities are protecting public health, maintaining safe air quality and preventing further disruption to schools, transport and outdoor activities.

Source: Reuters / Al Jazeera / ASEAN / VoS News