Haze in Singapore: PSI hits new high in central region

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.

PSI readings across all five regions in Singapore have remained largely in the unhealthy range for most of Oct 8 and Oct 9, with some areas dipping into the moderate range between 6pm on Oct 8 and 1am on Oct 9.

Since 2am, all regional readings have returned to the unhealthy range.

One-hour PM2.5 readings, measured in micrograms per cubic m, were also elevated in the other parts of Singapore at 2pm – east (116), west (144), south (120) and north (92).

The hourly PM2.5 reading is used as a gauge for immediate air quality, with scores from 56 to 150 indicating elevated pollution levels, while values of 151 to 250 represent high pollution levels.

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

Reduce outdoor activities

When the 24-hour PSI readings are in the unhealthy range, those who are healthy should reduce prolonged or strenuous outdoor physical activities, according to the National Environment Agency’s (NEA) haze advisory.

Vulnerable people – including the elderly, pregnant women, children and those with chronic lung or heart disease – should minimise or avoid such activities entirely.

When PM2.5 readings are high – between 151 and 250 – people should avoid strenuous outdoor activities for the next hour. Vulnerable people should avoid all outdoor activities.

These are outlined in the personal guide published on NEA’s website.

In its daily advisory on the evening of Oct 8, NEA forecast that the 24-hour PSI readings would be in the high-moderate to mid-unhealthy range.

NEA said moderate to dense smoke plumes from southern and central Sumatra and West Kalimantan were observed to be drifting towards Singapore, with dry conditions expected to continue in the neighbouring Indonesian territories.

“Under the prevailing south-easterly or southerly winds, smoke haze may continue to drift towards Singapore,” it added.