SINGAPORE- The three-hour Pollutant Standards Index (PSI) inched upwards into the unhealthy range on Sunday afternoon, hitting 110 at 4pm.

The reading was 104 an hour earlier.

Two weeks ago, Singapore was also shrouded in haze with readings above 100, which is the unhealthy range, prompting people to start wearing masks.

If the 24-hour index hits the unhealthy band, the National Environment Agency (NEA) recommends that healthy people should reduce prolonged or strenuous outdoor physical exertion, while the elderly, pregnant women and children should minimise such exertion