Haze clears in Singapore as air quality improves to moderate levels nationwide

SINGAPORE, 1 OCTOBER 2026 —

Singapore’s 24‑hour Pollutant Standards Index (PSI) fell back into the moderate band across all regions by 11 pm on 30 September, after a brief spike that pushed the central region into the unhealthy range earlier that day.

The PSI for the central region was 99 at 11 pm, while the other regions recorded values between 81 and 99, down from a peak of 134 in the central and western regions at 1 am.

The unhealthy spike was part of a broader haze episode that began on 29 September when the PSI in the central region reached 164 at 10 am, the highest reading of the season and the first time the index breached the unhealthy band (101–200) in two weeks. That same day, all five regions exceeded the 101 threshold, a pattern last seen on 15 September.

The central region’s earlier peak of 154 on 15 September had been the previous season’s high.

The PSI is a 24‑hour rolling average of six key air pollutants and is used by the National Environment Agency (NEA) to advise the public on outdoor activity planning.

PSI readings of 51 to 100 are considered moderate, while 0 to 50 are “good.” The NEA’s daily haze advisory on 30 September forecast the 24‑hour PSI to remain in the “moderate to low unhealthy” range, citing an improvement in the haze situation with showers over Singapore and the surrounding region. Dry conditions are expected to persist over parts of southern Sumatra and south‑western Kalimantan, while showers are forecast over Singapore again on 1 October.

The prevailing winds are expected to blow from the south‑east or south, maintaining a risk of smoke haze affecting the Republic.

Hourly PM2.5 readings, which indicate current concentrations of fine particulate matter, were all within the normal band at 11 pm on 30 September, ranging from 18 to 37. PM2.5 values between 56 and 150 are considered elevated, and 151 to 250 are high. The NEA advises the public to consult the hourly PM2.5 reading for immediate activity decisions and the 24‑hour PSI for day‑ahead planning.

The PSI first crossed into the unhealthy range about four weeks earlier, hitting 101 in central Singapore on the morning of 4 September. In the days that followed, readings in the central, eastern and western parts of the island occasionally crossed into the unhealthy range. The September developments mark the first time since October 2023 that the PSI in Singapore hit unhealthy levels because of haze.

Authorities had earlier warned of a haze risk between June and October, citing warmer and drier conditions driven by both El Niño and the Indian Ocean Dipole.

The NEA’s daily haze advisory on 30 September noted that showers over Singapore and the surrounding region had helped improve the haze situation, but the risk of smoke haze remains due to prevailing wind directions. The agency continues to monitor the PSI and PM2.5 levels closely and will issue further advisories as conditions evolve.