SINGAPORE - Local vegetation fires and wind convergence over Singapore could have contributed to the burning smell detected in some parts of the island on Tuesday (March 29), said the National Environment Agency (NEA).

While hot spot activities in the region have been low, there has been a rise in the number of hot spots in the northern Asean region which is currently experiencing its traditional dry season, NEA added in a press release on Wednesday.

These factors could result in an increased concentration of particulate matter such as dust particles in the atmosphere.

This would have led to the burning smell and slight deterioration in the air quality in some parts of Singapore on Tuesday night and early Wednesday morning, NEA said.

As at 8pm on Wednesday, the 24-hr PSI reading is 66-84, in the moderate range. The air quality for the next 24 hours is expected to remain in this range, NEA said.

Weather forecast showed that air and warm conditions are expected for the rest of the day, with prevailing winds blowing from the north-east.

The 24-hour PSI has hovered nearer 40 to 60 in recent months, and Tuesday night's PSI reading was the first noticeable spike this year.

The three-hour PSI, which is not tied to health advisories, was 89 at 8pm, following a short spike the night before when it hit 87 at 8pm.

Singapore suffered one of its worst bouts of haze in 2015 with the extended El Nino season.

PSI readings reached hazardous levels in September 2015, leading to the closure of primary and secondary schools.

For updates, visit the NEA website, the haze microsite, follow NEA Facebook and NEA Twitter, or download the myENV app.