There were slightly clearer skies over Singapore on Saturday, even though forest fires continued to rage in Sumatra.

The Pollutant Standards Index (PSI) eased slightly from last Friday's peak of 88 but remained in the "moderate" range, with the three-hour reading for the island hitting a high of 79 at 6pm.

A PSI reading of zero to 50 is "good", while anything above 100 is considered "unhealthy".

At 4pm yesterday, the 24-hour PSI readings in different parts of the island ranged from 66 to 89.