Haze in Singapore persists; 24-hour PSI remains unhealthy for all regions

SINGAPORE – Hazy conditions across Singapore remained overnight, with the 24-hour PSI for all regions staying within the unhealthy range.

At 6am, the highest 24-hour Pollutant Standards Index reading was recorded in the west at 173, followed by the central region (166), the east (148), the south (131) and the north (126).

Air quality is considered unhealthy when the PSI – a 24-hour rolling average of six key air pollutants – is in the range of 101 to 200.

The hourly PM2.5 readings – measured in micrograms per cubic m and used as a gauge for current air quality – were in the elevated zone for four regions of Singapore: central (110), east (99), west (97) and south (76).

Only the north region (55) recorded readings in the normal zone, at the threshold of entering the elevated band.

PM2.5 scores from 0 to 55 represent normal values, those between 56 and 150 indicate an elevated concentration of fine particles, while those between 151 and 250 are considered high.

In its daily haze advisory in the evening of Oct 12, the National Environment Agency (NEA) forecast the 24-hour PSI for Singapore to be in the unhealthy range.

It said: “Moderate to dense smoke plumes continued to be observed from fires in Kalimantan and southern Sumatra. Under prevailing south-easterly winds, smoke haze was observed drifting towards Singapore.”

While some showers are expected over Singapore and parts of the surrounding region, dry conditions are forecast to persist over parts of southern Sumatra and Kalimantan, said NEA.

Smoke haze may continue to drift towards Singapore under the prevailing easterly or south-easterly winds, added NEA.

For the first time since October 2023, air quality in Singapore breached unhealthy levels for the first time on Sept 4. The NEA began issuing daily haze advisories since the evening of that day.

The PSI reached a peak for 2026 on Oct 9, reaching 192 in the central region between 5pm and 8pm.

The highest hourly PM2.5 reading to date in 2026 was recorded in the west at 2am on Oct 9, peaking at 171.

The government’s haze task force announced a series of measures on Oct 9 should the PSI exceed 200 and move into the very unhealthy range.

Daniel Lai is a journalist at the ST Now team, covering breaking news and international affairs.