Singapore is currently experiencing its most severe transboundary haze episode in over a decade, as air quality deteriorated to the "very unhealthy" range on October 14. The haze, which has also affected Malaysia and parts of Indonesia, is primarily caused by widespread fires on forest and plantation lands in Indonesia.

These fires are frequently linked to illegal slash-and-burn agricultural practices, where farmers set fires to clear land for crops due to lower costs compared to mechanical clearing methods. Although such methods have been common in the region, this year’s situation has intensified due to a combination of three key factors.

Firstly, the equatorial ASEAN region is undergoing its typical dry season, which usually spans from June to September. However, in 2026, this dry period has been extended by the presence of a strong El Niño phenomenon, exacerbating heat and dryness across the region. Winds blowing from southern Indonesia carry smoke from the fires toward Singapore and Malaysia, spreading the haze.

Secondly, the 2026 El Niño event is expected to be among the strongest since 1950. This weather pattern shifts winds and warm water eastward, pulling rain clouds away and resulting in drier, hotter conditions across Southeast Asia. The last comparably severe El Niño, in 2015, coincided with the region’s worst haze crisis in recent history.

Thirdly, the drainage of peatlands in Indonesia has contributed significantly. Peat soils, which store vast amounts of carbon, are normally waterlogged. However, to cultivate cash crops like oil palm and pulpwood, peatlands are often drained, releasing stored carbon and leaving the landscape prone to fire. When dry, peat can smoulder underground for months, producing persistent smoke that only usually dissipates when the rainy monsoon season begins around November or December.

In response to the fires, Indonesian authorities have identified over 200 individuals and nine companies suspected of involvement in illegal burning activities. Additionally, more than 50 business entities have been shut down for fire-related violations.

The haze has led to deteriorating air quality and increased respiratory health problems across the affected countries, straining healthcare systems. It has also disrupted transportation, with flights delayed or diverted due to poor visibility. In Singapore, authorities have distributed N95 masks and opened air-conditioned shelters at community centres and residences for the elderly. Schools in Johor Bahru, Malaysia, were closed for several days, and some malls and outdoor venues in Singapore have limited operations.

The situation has prompted protests in Indonesia and calls from various groups for stronger enforcement against those responsible for the fires and more effective firefighting measures. Regional meteorological organizations continue to monitor conditions closely as the haze episode persists.