In a statement, NEA said that Pollutant Standards Index (PSI) have increased since 5pm. The 24-hour PSI at 8pm stands at 42-50, placing it in the "Moderate" range.
The agency reported that the haze may be due to hotspots north of Singapore, that were blown in by northeasterly winds. Four hotspots were detected in Peninsular Malaysia today, and 35 hotspots detected in Sumatra, Indonesia.
A total of 4 hotspots were detected in Peninsular Malaysia today, and 35 hotspots in Sumatra. - See more at: http://app2.nea.gov.sg/corporate-functions/newsroom/advisories/haze-hotspot-situation-update-(7-mar)#sthash.9oOxcBMD.dpuf
It also said that the hazy condition is expected to continue overnight, and that the agency will continue to monitor the situation.
Check out more pictures of the haze in Singapore: