Singapore's Entire Island Records Unhealthy PSI Simultaneously for First Time Since 2019

All five of Singapore's PSI regions crossed into the unhealthy (101-200) 24-hour band simultaneously on the morning of Sept. 15 — the first time that has happened since September 2019 — as smoke plumes from Kalimantan and southern Sumatra intensified overnight. NEA's 6am readings peaked at Central 154, West and East both 128, South 111 and North 104; by 9am Central had eased slightly to 148 but remained the worst-affected region. Conditions improved through the afternoon as overnight showers over parts of Kalimantan helped clear some haze: NEA's 6pm advisory put the 24-hour PSI in a 92-131 range (North and South back to moderate at 92 and 91; East, West and Central still unhealthy at 111, 112 and 130). NEA said dry conditions were expected to persist over central/southern Sumatra and southern Kalimantan in the coming days, with southeast-to-south winds continuing to pose a haze risk, and forecast the next 24 hours would stay in the 'high moderate to mid-unhealthy' range. The milestone put Singapore among the world's 10 most polluted major cities that day per IQAir, and followed more than 7,000 Indonesian fire hotspots detected so far in September after an already-elevated 9,000+ in August.