The haze is back, as smoggy skies and a burning smell in the air hung across many parts of Singapore on Friday.

The three-hour Pollutant Standards Index (PSI) stood at 85 at 6pm on Friday, slightly lower than the 88 at 5pm. This is at the higher end of the "moderate" range of 51 to 100. Meanwhile, the latest 24-hour PSI average, measured at 4pm on Friday, stood between 59 and 65, also within the "moderate" range.

The last time air quality here deteriorated to unhealthy PSI levels - when the index passes 100 - was in 2010. This was also caused by haze attributed to forest fires in Indonesia.

The National Environment Agency (NEA), in a situation update on Wednesday, said that "occasional extended periods of drier weather" can be expected in the coming months, resulting in increased hotspot activities in Sumatra and Borneo.