Singapore haze PSI readings return to moderate as Sumatra and Kalimantan fires persist

Air quality across Singapore improved to moderate levels on the evening of 20 September 2026, with the central region's 24-hour Pollutant Standards Index dropping from a peak of 120 at 10am to 100 by 7pm. The National Environment Agency forecast moderate to unhealthy PSI conditions to continue, driven by dry conditions in southern Sumatra and south-western Kalimantan and prevailing south-easterly winds. Smoke haze risks are compounded by El Niño and Indian Ocean Dipole effects, and NEA noted the PSI first entered the unhealthy range on 4 September in the central region.