Winds blowing from the south and south-east will carry the haze away from Singapore today.

The prevailing winds are forecast to blow from the south-east or south, the National Environment Agency (NEA) said in an advisory yesterday evening.

The Pollutant Standards Index (PSI) is forecast to be in the moderate range.

The 24-hour PSI entered the unhealthy range for the first time this year last Friday.

It improved over the weekend, but inched back into the unhealthy range in the north yesterday morning before falling back to moderate after 3pm.

Air quality is considered unhealthy when the 24-hour PSI is in the 101-200 range.

It was in the high end of the moderate range in the rest of Singapore yesterday.

The one-hour PM2.5 concentration was within the normal range for most of yesterday.

It is expected to stay in the Normal band, which is below 55, today.

One hot spot was detected in Sumatra but the low count was due to cloud cover, said NEA.

"Showers over parts of central Sumatra (on Monday) have helped to reduce the extent of the haze there," the agency said.

"Some haze was still observed over the Strait of Malacca."

Thundery showers are also expected this morning in Singapore.

Given the air quality forecast, everyone can continue with normal activities, NEA said.

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

Chew Hui Min