Indonesia wildfire smoke linked to 3,560 deaths in September

Focal Brief

Smoke from Indonesia’s forest and land fires caused an estimated 3,560 premature deaths in September 2026, according to a Centre for Research on Energy and Clean Air assessment released October 29, with Kalimantan and Sumatra bearing the heaviest fire-related toll.

Focal Facts

• CREA estimated 5,310 air-pollution-related deaths in September, up 42% from 3,740 in August.
• Fire smoke accounted for an estimated 3,560 deaths; urban and industrial pollution accounted for 1,750.
• A record 57.8 million people experienced unhealthy-to-hazardous air at September’s peak.

Focal Point

The next signal is whether daily PM2.5 exposure and the number of people breathing unhealthy air decline as rainfall and firefighting operations intensify—or remain elevated beyond the September peak.

The figure is a modelled estimate rather than a count from individual death certificates. CREA combined daily fine-particle pollution data, readings from 186 ground monitors, provincial mortality data and concentration-response functions to estimate deaths occurring within days of exposure.

The group calculated that Indonesia’s population-weighted PM2.5 concentration averaged 36 micrograms per cubic metre in September, more than seven times the World Health Organization’s annual guideline. It attributed 94% to 99% of air-pollution-related deaths in four Kalimantan provinces to fire smoke, with the share exceeding 80% in several Sumatran provinces. Java’s burden remained predominantly linked to urban and industrial emissions.

Indonesia’s government says it has deployed tens of thousands of personnel and intensified aerial firefighting and weather-modification operations. The consequential question is whether those measures and seasonal rain will reduce smoke exposure quickly enough to prevent another month of elevated mortality.