PUBLISHED ONSeptember 19, 2026 10:20 AMBYSean LerAir quality in the Republic worsened on Saturday (Sept 19) afternoon as the 24-hour Pollutant Standards Index (PSI) in central Singapore entered the unhealthy range at 1pm.
One-hour PM2.5 in the central region also bordered the high-band at 12pm, hitting a high of 149 µg/m3. Readings between 56 and 150 are in the elevated band.
At 6pm, the 24-hour PSI reading ranged from 83 to 108. This is in the moderate to unhealthy range.
The highest PSI reading of 108 was recorded in central Singapore, while the next highest readings were in eastern (93) and western (96) Singapore.
Meanwhile, one-hour PM2.5 is in the normal band for all regions, except in central Singapore, where the concentration reading is 61.
In its daily haze update on Saturday evening, the National Environment Agency (NEA) said the country's 24-hour PSI forecast is expected to remain in the high-moderate to mid-unhealthy range.
This is due to prevailing winds blowing from the east-southeast or southeast, which has brought smoke plumes from fires in Kalimantan and southern Sumatra towards Singapore, the agency explained.
"There is a risk of smoke haze affecting Singapore," NEA added.
Members of the public can refer to the one-hour PM2.5 reading if planning to participate in outdoor activities immediately, or the 24-hour PSI forecast for next-day activities.
They should note that the health impact of haze is dependent on one's health status, the PSI level, and the length and intensity of outdoor activity.
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