Singaporeans posted on social media photos of the hazy Singapore skyline as they detected burning smell in parts of the nation on Friday morning.
According to the National Environment Agency (NEA), as at 10 am (Singapore local time), the 24-hour Pollutant Standards Index (PSI) was 51-62 in the moderate level.
The three-hour PSI was 111 up from 90 at 8 am.
The 1-hour PM2.5 reading hit 150 in western Singapore at 10 am, followed by 102 in the north of Singapore. But the reading is the lowest in the eastern part of the country indicating 33.
The index incorporates six types of pollutants such as sulphur dioxide, particulate matter that is 2.5 micrometres in diameter or smaller (PM2.5), particulate matter that is 10 micrometres in diameter or smaller (PM10), ozone, nitrogen dioxide and carbon monoxide.
Among all these six pollutants, PM2.5 is considered to be highly hazardous. The small size of the particles of PM2.5 enters the human lungs more easily than the others.
NEA said it will issue an advisory regarding this haze issue.
Earlier in March, a similar sort of burning smell was detected in Singapore but at that time NEA had said that it could have been caused by some local vegetation fires.