SINGAPORE, Sept 5 — Singapore’s air quality improved on Saturday morning, with the western region returning to the moderate range after briefly recording unhealthy levels earlier in the day.

At 9am, the 24-hour Pollutant Standards Index (PSI) – similar to Malaysia’s Air Pollution Index – stood at 115 in the central region, while the west recorded 98 and the east 96, The Straits Times reported.

The west had entered the unhealthy range at 102 at 7am, making it the third region in Singapore to breach the 101 threshold since Friday.

The north and south remained in the moderate range, with readings of 83 and 87 respectively.

Singapore’s National Environment Agency (NEA) considers PSI readings of 101 to 200 unhealthy and advises people to reduce outdoor activities at such levels.

Checks by The Straits Times showed that the west had crossed the 101 threshold at around midnight.

The east entered the unhealthy range at about 9pm yesterday and remained there until its reading fell at 7am today.

The latest reading means the central region has now recorded unhealthy air quality for more than a day.

The last time Singapore recorded unhealthy PSI levels due to haze was in October 2023.

Yesterday, the NEA said the haze could persist today, with air quality expected to range from the higher end of moderate to the middle of the unhealthy range.

The agency said smoke plumes from fires in southern and central Sumatra and various parts of Kalimantan had been observed drifting towards Singapore.

With dry conditions forecast in the coming days, Singapore could continue to experience transboundary haze if wind directions remain unchanged while the fires persist.