Haze watch: Air quality worsens in Singapore as PSI hits unhealthy range in all 5 regions

Residents in Singapore woke up to unhealthy air quality as 24-hour Pollutant Standards Index (PSI) entered the unhealthy range for all five regions on Tuesday (Sept 29).Central and southern Singapore entered the range at 8pm on Monday, followed by the western and eastern regions at 9pm and midnight respectively.The northern region crossed the threshold at 7am on Tuesday. At 8am, PSI ranged from 103 to 158 — in the unhealthy range — with central Singapore recording the highest reading of 158. This is followed by the western (143), eastern (130), southern (129) and northern (103) regions.Meanwhile, one-hour PM2.5 is in the elevated band in the central (116), western (100), eastern (80) and northern (67) regions, with only southern (51) Singapore remaining in the normal band.The concentration reading hit the high band for the first time in the ongoing haze season at midnight, recording a high of 165.Readings of between 151 and 250 denote the high band.