Haze pushes air quality into the unhealthy range across Singapore. NEA expects no quick relief on Tuesday
The 24-hour PSI crossed 101 in every region on Monday, a month after the first unhealthy readings since 2023. Smoke from fires in Sumatra and Kalimantan is drifting in on south-easterly winds.
Singapore spent Monday under a grey sky. The Straits Times reported that air quality fell back into the unhealthy range overnight, and by the afternoon both CNA and the Straits Times said the 24-hour PSI was in the unhealthy band in all regions of the island. The PSI is a rolling 24-hour average of six pollutants, and readings from 101 to 200 count as unhealthy. On Sunday morning only the central region had crossed that line, at 102. The spread to every region on Monday marks the worst day of the current episode so far.
The National Environment Agency forecast that Tuesday's 24-hour PSI would sit between the high moderate and mid unhealthy range, because winds were expected to keep blowing from the south-east or east-south-east. That direction carries smoke from land and forest fires in southern Sumatra and Kalimantan. Regional weather forecasters have warned of strong El Niño conditions and below-normal rainfall over much of South-east Asia from September to November, which keeps peatland dry and makes fires harder to put out.
This is not a short spell. Singapore first slipped into the unhealthy range on 4 September, for the first time since 2023, and the haze has come and gone since then. CNA published an explainer on Monday on the billions of dollars the region has lost to past haze episodes, and on why prevention efforts across South-east Asia keep falling short. The same pattern is showing up elsewhere: the Straits Times reported that Myanmar has warned of power cuts linked to El Niño.
For most people the practical question is simple: whether to go outside. NEA's standing advice for the unhealthy range is for healthy people to cut down on prolonged or strenuous outdoor exercise, and for the elderly, pregnant women and children to keep such activity to a minimum. People with chronic lung or heart conditions are told to avoid it. The timing is awkward for the city's busiest sporting week: the Formula One race weekend arrives later this week, and outdoor fan events are already under way. Organisers have not announced any changes. DailyDrop will watch the morning PSI and NEA's three-day outlook.
Some things remain unclear. We could not confirm an official count of fire hotspots in Indonesia for Monday, and figures circulating online appear to come from earlier haze years, so we have left them out. Nor is there yet an estimate of what this episode is costing Singapore. What is clear is the pattern of the past month: readings rise when the wind turns south-easterly and ease when it shifts. That makes the wind forecast, more than any single day's reading, the best guide to the week ahead. Until the inter-monsoon rains arrive in earnest, hazy days are likely to recur.