Singapore’s National Enviroment Agency (NEA) says with the expected transition from the North-East Monsoon to the inter-monsoon period in the second half of March, winds in the region will turn light and variable in direction.

“This may pose some risk of transboundary haze affecting Singapore should the hotspots in Sumatra persist and the prevailing winds in our region temporarily turn westerly,” it said in a statement.

The inter-monsoon period typically lasts from late March to May.

NEA said the prolonged dry weather affecting parts of the region the last two months has resulted in an escalation of hotspot activities in central and northern Sumatra since early February.

It said smoke plumes and widespread moderate to dense haze are visible in Riau province.

In the past week, elevated hotspot activities were also detected in parts of peninsular Malaysia.

Yesterday, six and 47 hotspots were detected in Sumatra and peninsular Malaysia respectively.

The low hotspot count for Sumatra was due to cloud cover and partial satellite coverage.

NEA said although increased rainfall can be expected later in the month, total rainfall for March is forecast to be below average in most parts of the region.

The air quality between 8pm Tuesday night and 4am yesterday deteriorated slightly into the moderate range.

The 24 hour Pollutant Standards Index (PSI) range over that period was 51 to 52.  This was due to accumulation of particulate matter in the atmosphere under converging wind conditions.

The air quality has been in the good range since 5am yesterday. NEA will continue to monitor the situation.

- Bernama