Singapore and Kuala Lumpur are currently facing a deterioration in air quality due to transboundary haze linked to forest fires in Indonesia.
According to IQAir data, both cities ranked among the five most polluted cities in the world as of September 30, 2026. Dry conditions and winds blowing from the east to southeast are expected to persist for about a week, potentially prolonging the hazy conditions.
Malaysia is facing this situation just as several major sporting events are set to take place. The Formula 1 race is scheduled to return to the Sepang International Circuit for the first time in nine years, while the Standard Chartered Kuala Lumpur Marathon is also taking place this weekend.
Marathon organizers are considering contingency plans should conditions worsen.
Haze Expected to Persist
Singapore has also been affected; a half-marathon event last weekend was shortened at the last minute due to poor air quality.
According to Fergus Keatinge, founder and director of WeatherMapping.com, Singapore's air quality can fluctuate based on wind direction and local rainfall, yet there are no clear changes in weather patterns to indicate an end to the haze in the immediate future.
This haze season is said to be one of the worst in recent years, with hot and dry conditions in Indonesia increasing the risk of fires. Rainfall across the archipelago since June has reportedly been about 80% below normal levels, while the monsoon rains are expected to arrive late. The Indonesian Ministry of Forestry's fire monitoring platform recorded 15,461 hotspots throughout September, surpassing 2019 levels and falling just short of the 2015 record.
Singapore's Air Quality Reaches Unhealthy Levels
As of early Wednesday, four out of five regions in Singapore recorded air pollution levels in the "unhealthy" range, according to Singapore's National Environment Agency.
The agency stated that hotspot and haze conditions could improve in areas receiving rainfall but might remain elevated in regions experiencing prolonged dry weather.
This situation is also drawing attention ahead of the Singapore Formula 1 race, scheduled to begin on October 9, following the race in Malaysia.
