Air quality in Singapore's central region back in unhealthy range; 24-hour PSI reading at 108

SINGAPORE, 27 SEPTEMBER 2026 —

Singapore’s central region air quality deteriorated on Saturday, September 26, as the 24-hour Pollutant Standards Index (PSI) crossed back into the unhealthy range.

While the central region entered the unhealthy category, readings in other parts of the island remained in the moderate range. At 8 pm, the north recorded 74, the south 78, the east 90, and the west 88. By 10 pm, these figures had increased slightly, with the north at 78, the south at 83, the east at 96, and the west at 94.

Hourly PM2.5 readings, which indicate current concentrations of fine particulate matter, were in the elevated band in several areas. At 8 pm, the highest hourly PM2.5 reading was in the central area at 110, followed by the east at 88, the west at 82, and the south at 67. The north remained in the normal range at 50.

By 9 pm, the central area’s hourly PM2.5 reading spiked to 131, while the north climbed to 69, placing all other regions in the elevated range.

The National Environment Agency (NEA) issued a daily haze advisory at approximately 6 pm on September 26, forecasting that air quality for the next 24 hours would remain in the moderate to low-unhealthy range. The agency noted that while some showers are expected over Singapore and parts of the region overnight and on September 27, dry conditions are anticipated to persist over southern Sumatra and southern and eastern Kalimantan.

NEA stated that winds forecast to blow from the south-east or south-west could transport smoke haze to Singapore.

Air quality is classified as unhealthy when the 24-hour PSI falls between 101 and 200. An hourly PM2.5 reading between 56 and 150 indicates an elevated concentration of fine particles. In response to these conditions, NEA advised the public to use hourly PM2.5 readings for immediate activity planning and 24-hour PSI readings for broader daily planning. For periods when air quality is unhealthy, the agency recommended that healthy individuals reduce prolonged or strenuous outdoor activities.

Vulnerable groups, including the elderly, children, pregnant women, and those with chronic lung or heart disease, were advised to minimize or avoid such activities entirely.

This deterioration follows a period of improved air quality, with the PSI first returning to the unhealthy range on September 4, the first instance since October 2023. During that earlier period, readings in the central region were the highest, peaking at 154 on September 15.

The Meteorological Service Singapore had previously noted in its fortnightly weather forecast on September 16 that more showers are expected in the second half of the month compared to the first.

The current situation shows the ongoing impact of transboundary haze, driven by dry conditions in neighboring regions. As winds shift, the potential for further smoke transport remains a key factor for regional air quality. The NEA’s advisory highlights the need for continued monitoring of both hourly and daily indices to manage health risks effectively.

Related: National Environment Agency · Singapore