The haze that shrouded yesterday's skies is expected to persist today, due to winds blowing in smoke from Sumatra, Indonesia, where forest fires are still raging.
Air quality is forecast to be in the low- to mid-section of the unhealthy range and may enter the high section if denser haze is blown in, the National Environment Agency (NEA) said yesterday.
Air quality is considered unhealthy when the 24-hour Pollutant Standards Index (PSI) reading is in the range of 101 to 200.
Reduced visibility is also expected if the PM2.5 concentration - referring to particles which are 2.5 microns or smaller - remains elevated, it added.
Singaporeans may get some relief towards the end of this month, with the south-west monsoon season coming to an end.
The inter-monsoon period that follows typically brings more rain and light, variable winds to Singapore and the region, and should ease the haze situation, according to the Meteorological Service Singapore (MSS).
However, it added that Singapore could still be affected by the haze, depending on the location and extent of the fires in Sumatra and Kalimantan, the direction of the prevailing winds and the frequency of rain.
Yesterday, the 24-hour PSI entered the unhealthy range in the afternoon.
By 10pm, the 24-hour PSI was between 111 and 138. The three-hour PSI - an indicative reading not tied to a health advisory - rose to 183 at 5pm, from below 100 in the morning.
The total number of hot spots detected in Sumatra yesterday was 58. The NEA noted that parts of central and southern Sumatra are still affected by moderate to dense haze, and some of the haze has spread to the Strait of Malacca and the sea south of Singapore.
On Saturday, haze caused by intensified forest and land fires in Indonesia's Central Kalimantan spread to Sulawesi Island to its east for the first time this year.
A multinational taskforce which has been fighting the fires in Sumatra for the past week has had some success.
But dry weather in Indonesia, made worse by an extended El Nino season, has made it harder to douse the blazes completely.
•Additional reporting by Chew Hui Min
