"Red" haze outlook in 2026: Brunei, Indonesia, Malaysia, Singapore told to prepare for severe transboundary haze

Experts warn that the return of El Niño this year could likely produce a stronger, more prolonged dry season and higher fire risk across Southeast Asia, raising the likelihood of severe transboundary haze that may peak in August–September.

There is a red (high) risk of a severe transboundary haze event affecting Brunei, Indonesia, Malaysia and Singapore in 2026, according to the Singapore Institute of International Affairs' (SIIA) Haze Outlook 2026 report. The alert uses a three-tier scale — green, amber, and red — and signals a heightened probability of widespread smoke and air-quality impacts across the region.

According to the report, meteorologists warn that the return of El Niño this year, potentially reinforced by a positive Indian Ocean Dipole (IOD), could produce a longer, stronger dry season — conditions that increase the likelihood of large fires. Those climatic pressures are arriving at a time when fire-preparedness may be weakened by economic uncertainty.

<Read our past coverage on how El Niño is affecting weather conditions in Singapore and Malaysia here>

Past haze outbreaks have usually coincided with severe droughts. This year’s weather patterns could potentially mean the remaining months of 2026 could be among the hottest and driest on record, making it much easier for land fires to grow and spread out of control.

El Niño conditions are already in development as of June 2026, and the US National Oceanic and Atmospheric Administration (NOAA) currently estimates a 63% chance of a strong El Niño. 

Climate change also raises the odds that 2027 could be the hottest year on record. At the same time, scientists say the IOD is harder to forecast; if a positive IOD lines up with El Niño this year, the region could see even hotter, drier conditions.

Here is a quick summary of how El Niño and the IOD affect haze risk:

• ENSO (El Niño–Southern Oscillation) is the name for the El Niño / La Niña cycle. It’s tracked by how much sea-surface temperatures in the central and eastern Pacific deviate from average. Sustained warm anomalies of about 0.5–0.8°C indicate El Niño; a very strong El Niño can reach around 2°C above average.
• The IOD is a similar pattern, but in the Indian Ocean. A sustained positive IOD (about 0.4°C or higher) tends to reduce rainfall over parts of Southeast Asia.
• For ASEAN countries, sustained positive values in either El Niño or the IOD increase the chance of below‑normal rainfall and drier conditions.
  • Historically, the worst haze events occurred when a strong El Niño and a positive IOD coincided (for example, 1997–98, 2015 and 2023). A positive IOD alone has also driven major episodes, such as the 2019 haze. It is rare, though not impossible, for severe haze to happen without one of these climate drivers.

Aaron Choo, Senior Assistant Director, Special Projects and Sustainability, SIIA stated that the 1997 to 1998 haze caused US$9.3bn (S$12bn) in economic losses across Southeast Asia, while the 2015 haze resulted in some US$16.1bn (S$20.6bn) of losses in Indonesia alone.

Other key findings from the report include:

• Fire prevention and land management efforts face a major stress test
• Rising demand for agricultural commodities and biofuels could increase land-use pressures
• ASEAN cooperation and sustainable land management will be critical to reducing risks

Simon Tay, Chairman of the SIIA, stressed: "ASEAN needs to take greater ownership of this challenge as the region enters a potentially severe dry season and faces the longer-term impacts of climate change. Supporting solutions with adequate funding will be critical."

More information on the report can be found here.

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Lead image / SIIA