Singapore’s air quality returned to moderate levels early on Sept 28 after haze pushed readings into the unhealthy band a day earlier, according to the National Environment Agency (NEA). The 24-hour Pollutant Standards Index (PSI) reading for the central region dropped to 80 by 6am on Sept 28, while the northern, southern, eastern, and western regions registered at 62, 68, 74, and 68 respectively.
Air Quality Slips into Unhealthy Range on Sept 27
At 7am on Sept 27, 24-hour PSI readings reached 128 in the central region, 115 in the east, and 106 in the west, while northern and southern readings stood at 89 and 95.
By 9pm on Sept 27, the eastern region’s PSI fell to 99—just below the 101 threshold that defines the unhealthy band—while northern, southern, and western regions recorded 78, 85, and 90. The central region peaked at an unhealthy 110 before dropping to 95 at midnight. Air quality is categorized as unhealthy when the 24-hour PSI ranges between 101 and 200, or when hourly PM2.5 readings measure between 56 and 150.
Decathlon Race Modified Due to Haze
The deteriorating air conditions forced organizers to modify Decathlon’s inaugural Kiprun race on Sept 27. The event’s 21.1km half-marathon was shortened to 10km, while shorter formats including the 10km, 5km, and the 670m Kids Dash proceeded without distance changes.
The NEA issued a daily haze advisory warning that air quality for the subsequent 24 hours would remain in the moderate to low-unhealthy range. While forecasters predicted showers over Singapore and parts of the surrounding region on Sept 28, dry weather persisted across southern Sumatra and southern Kalimantan. Prevailing south-easterly winds left Singapore exposed to an ongoing risk of smoke haze, according to the NEA.
Official Health Advisories and Seasonal Context
Environmental authorities advised the public to consult hourly PM2.5 readings when planning immediate outdoor activities and to check 24-hour PSI figures for daily scheduling. During periods of unhealthy air quality, the NEA recommends that healthy individuals reduce prolonged or strenuous outdoor exertion. Vulnerable populations—including children, the elderly, pregnant women, and individuals with chronic heart or lung disease—were advised to minimize or entirely avoid strenuous outdoor activities.
The late-September haze events follow earlier pollution spikes in the month. The PSI first re-entered the unhealthy range on Sept 4 for the first time since October 2023, with central region readings peaking at 154 on Sept 15. The Meteorological Service Singapore noted in its fortnightly weather forecast on Sept 16 that increased rainfall was expected during the second half of the month.
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