There is "some risk" of the haze returning in the second half of this month, the National Environment Agency (NEA) has warned.
That is when north-east monsoon winds - which have so far kept the dense haze in Sumatra at arm's length from Singapore - may begin to weaken, the agency explained in an advisory on Thursday.
The coming inter-monsoon period, which typically lasts from late March to May, brings light winds from different directions.
The haze may return if westerly winds begin to blow from Sumatra towards Singapore.
The NEA noted that the prolonged dry weather in this region has caused the number of hot spots in Sumatra, Indonesia, to rise since early last month. This has already caused smoke plumes and dense haze in Riau province in central Sumatra.
On Monday, Nasa satellites detected 337 hot spots of forest and plantation fires in Riau, which lies directly across the Strait of Malacca from Singapore. Its capital Pekanbaru is 280km from the Republic.
An unusual dry spell in Riau since late December has seen farmers take the opportunity to clear land by starting fires, which are causing the haze. The dry season there is from April to June.
The NEA said it would continue to monitor the situation.
Last June, Singapore suffered its worst haze, with pollutant levels reaching a record high. The country is also experiencing one of its longest-ever periods of dry weather, with little rain since mid-January. On Tuesday, the NEA said last month was Singapore's driest since 1869.
To conserve water, property heavyweight CapitaLand said that external water features will be shut off at the majority of its properties here, and non-essential cleaning such as that for facades and carparks postponed.
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