Same haze cloud over all of Singapore. So why did central hit PSI 154 while the north sat at 104?
On 15 Sept 2026, every region crossed into "unhealthy" for the first time since 2019 but unevenly: north 104, south 111, east/west 128, central 154 (worst). The smoke's source is regional (fires in Sumatra and Kalimantan, blown in by southeast winds) but where it settles hardest inside Singapore comes down to local density and ventilation, not the fires themselves.
Geography concept: a reminder that "Singapore" isn't one uniform environment even for something blowing in from outside it.
Exam skill: "why does X vary within Singapore" answers need two aspects, the regional cause, then the local factor that traps or disperses it. One dimensional answers lose marks.
https://www.channelnewsasia.com/singapore/singapore-haze-psi-unhealthy-6382851?cid=internal_sharetool_iphone_16092026_cna
