SINGAPORE — Residents in Singapore woke up to unhealthy air quality again with three regions in the unhealthy range today morning.

The 24-hour Pollutant Standards Index (PSI) turned unhealthy in central Singapore at 8pm yesterday, with the western and eastern regions also entering the range at 12am and 1am respectively.

Meanwhile, one-hour PM2.5 reached as high as 131 in central Singapore at 9pm yesterday before gradually easing back to the lower-end of the elevated band.

At 9am, PSI ranged from 90 to 130 — in the moderate to unhealthy range — with central Singapore recording the highest reading of 130.

One-hour PM2.5 is the normal band for the northern, western and southern regions, while central (68) and eastern (58) Singapore have an elevated concentration reading.

In its daily haze situation update yesterday evening, the National Environment Agency (NEA) had said the country’s 24-hour PSI forecast is expected to be in the moderate to low-unhealthy range.