General : Haze: 22 Areas Record Unhealthy API Readings, IPD Serian Highest This Morning

The air quality in Singapore worsened on September 20 as the 24-hour Pollutant Standards Index (PSI) readings in the eastern and western areas reached the unhealthy range, joining the central region. At 7am, the PSI in the east and west measured 102 and 105 respectively, while the central region recorded 123. The north and south regions remained in the moderate range.

The central area's PSI entered the unhealthy range since 1pm on September 19, and the rest of the country had moderate air quality throughout the day. Air quality is deemed unhealthy when the 24-hour PSI falls between 101 and 200, prompting the National Environment Agency (NEA) to advise the public to limit outdoor activities. PSI readings between 51 and 100 are considered moderate, and values between 0 and 50 are in the "good" range.

The NEA predicted the 24-hour PSI to remain within the "high moderate to mid unhealthy" range following afternoon showers over central and western Singapore, despite dry conditions forecasted to persist over southern Sumatra and Kalimantan. Smoke haze from the region might impact Singapore due to prevailing winds blowing from the east-southeast or southeast.

This marks the first time since October 2023 that Singapore experienced unhealthy PSI levels due to haze, as authorities had warned of the risk during warmer and drier conditions caused by El Nino and the Indian Ocean Dipole.