Singapore 3-hour PSI reading crosses to 'unhealthy' level at 106

View from Marine Crescent. (Yahoo photo)

Singapore's air quality entered the "unhealthy" range Saturday afternoon, as the three-hour PSI reading hit as high as 106.

The reading reached 101 at 1pm then stayed at 106 from 2-3pm before falling back at 4pm.

This is the second time within less than a week that the PSI reading hit the "unhealthy" level. On Monday, it reached 153, the highest level this year.

"The haziness is due to smoke haze from our surrounding region, blown in by the prevailing southerly to southeasterly winds," NEA said it in its update at 2pm on Saturday.

Air quality is in the unhealthy level when the PSI reading ranges from 101 to 200.

At 4pm, the 24-hour PSI reading was at 76-84.