SINGAPORE - Singapore is experiencing hazy conditions on Tuesday (Sept 22), as the Pollutant Standards Index (PSI) edged into the low end of the unhealthy range.

The National Environment Agency (NEA) said in an update at 6pm on Tuesday that the current hazy conditions are expected to persist for the rest of Tuesday.

As of 11pm, the 24-hour PSI was 85 to 112. The three-hour PSI, which is not linked to any health advisory, was 65 at 11pm.

The 24-hour PSI has not breached 100 since Sunday morning.

The deterioration in the haze conditions since this afternoon was due to haze from Sumatra being blown in by prevailing south-southeasterly winds.

"The 24-hour PSI for the next 24 hours is expected to be in the low to mid sections of the unhealthy range, and may enter the high end of the unhealthy range if denser haze from Sumatra is blown in," NEA said.

On Wednesday, the prevailing winds are forecast to blow from the south-southeast or south-southwest.

Given the air quality forecast, it added that healthy people should reduce prolonged or strenuous outdoor physical exertion.

The elderly, pregnant women and children should minimise prolonged or strenuous outdoor physical exertion, while those with chronic lung or heart disease should avoid prolonged or strenuous outdoor physical exertion.

People who are not feeling well, especially the elderly and children, and those with chronic heart or lung conditions, should seek medical attention, NEA added.

For updates, visit the NEA website, the haze microsite, the NEA Facebook page and Twitter, or download the myENV app.