Indonesia’s 2015 haze is still too often described like a recurring nuisance, a weather problem, a regrettable side effect of development. That framing is morally evasive. Between June and October 2015, about 2.6 million hectares burned in Indonesia. More than 500,000 people reported respiratory illness. Harvard and Columbia researchers later estimated that the smoke may have caused more than 100,000 premature deaths across Indonesia, Malaysia, and Singapore. Another peer-reviewed analysis found that 69 million people were exposed to unhealthy air and estimated 11,880 excess deaths from short-term exposure alone.

The lethal mechanism was built into the land model.

El Niño intensified the drought, but drought was only the accelerant. The fuel was policy. Peer-reviewed research shows that deforestation and drainage made Indonesian peatlands newly vulnerable to fire. Once canals dry peat, fire no longer stays on the surface. It smolders underground, emits enormous quantities of PM2.5, and turns land-clearing into regional poisoning. A 2021 Nature Communications study estimated the 2015 fires caused $28 billion in losses when longer-term health impacts are counted, and concluded that completed peatland restoration could have prevented about 12,000 premature deaths in 2015 alone. This is not nature striking back. It is a supply-chain design failure.

How often accountability evaporated

The state knew where to look. Reuters reported in 2015 that Indonesia suspended four companies and was investigating more than 200 over haze-linked fires. But the legal record that followed was far weaker than the scale of harm demanded. A court later rejected the government’s case against PT Bumi Mekar Hijau, a supplier to Asia Pulp & Paper. In Riau, police dropped investigations into 15 firms the environment ministry had linked to the 2015 burning. By 2020, legal advocates were still saying enforcement had stalled around 349 palm, pulp, and paper companies tied to fires since 2015. Even Indonesia’s 2019 citizen-suit ruling said the government still had more to do, including naming landowners on burned land and issuing compensation rules.

The warning is current

This is not closed history. A 2024 study of the 2019 Indonesian peat fire crisis estimated more than 87,000 excess deaths nationwide from fire-induced PM2.5. Another 2024 study using 2023 dry-season measurements in Central Kalimantan found mean outdoor PM2.5 at 136 μg/m3, with 1.62 million people exposed to unhealthy, very unhealthy, or dangerous air. Meanwhile, Indonesia’s palm plantation moratorium expired in 2021, plantation area had expanded to 17.3 million hectares by 2024, and officials were still seizing millions of hectares and revoking permits in late 2025 and early 2026 over illegal forest operations and environmental breaches. The lesson for the world is blunt:

When drained peat, opaque concessions, and weak enforcement become normal, mass death returns disguised as haze season.