Haze watch: Air quality in Singapore deteriorates, central region PSI turns unhealthy

The 24-hour Pollutant Standards Index (PSI) returned to the unhealthy range in central Singapore on Saturday (Oct 3) morning, after two consecutive days of improved air quality. At 11am, PSI ranged from 76 to 102 — in the moderate to unhealthy range — with central Singapore recording the highest PSI of 102.Elsewhere, the eastern and western regions have the next highest readings of 94 and 91 respectively. PSI readings of between 101 to 200 are in the unhealthy range.Meanwhile, one-hour PM2.5 is in the elevated band in eastern (66), and central (63) Singapore.In its daily haze situation update on Friday evening, the National Environment Agency (NEA) had said that the country's 24-hour PSI is forecast to remain in the moderate to low-unhealthy range.It noted that moderate to dense smoke plumes from southern Sumatra were observed drifting towards Singapore, while smoke haze was also observed from fires in Kalimantan.