Air quality in northern and southern Singapore reached moderate levels on Saturday noon.

The Pollutant Standards Index's (PSI) three-hour reading was a "moderate" 52 and 51 in the north and south respectively. The western, central and eastern parts of the island had "good" readings of 43, 46 and 46 respectively.

According to the National Environment Agency's (NEA) website, all persons - regardless of age or health conditions - can continue to take part in normal activities during good and moderate PSI levels.

On Friday, air quality reached the worst level since the start of the year, with the haze affecting visibility and some complaining of a burning smell. The PSI reading hit a high of 71 at 8pm on Friday, and fell to 61 two hours later.

On Thursday, the NEA said that the transition from the northeast monsoon to the inter-monsoon period in the second half of March "may pose some risk of transboundary haze affecting Singapore".

The Riau province of Sumatra has been shrouded in dense haze over recent days as farmers set fires to clear land during the dry spell. On March 5, NEA detected six hotspots in Sumatra, Indonesia, and 47 hotspots in peninsular Malaysia. But it added that the low hotspot count for Sumatra was due to cloud cover and partial satellite coverage.