The haze in Singapore got worse on Thursday and could enter "hazardous" levels on Friday, the National Environment Agency (NEA) said in a press release on Thursday night.
It said that the Ministry of Education has, in consultation with the Health Ministry, decided to close all primary and secondary schools on Friday as a result and suspend lessons.
However, the Manpower Ministry has reiterated that there will be no "national shut-down" of workplaces, NEA said in its statement.
The agency noted that the 24-hour PSI reading in Singapore was 219-270 as at 9pm on Thursday, in the "very unhealthy" range. That was the highest PSI reading recorded so far this year, it said.
For Friday, it warned that the haze could persist. The PSI could remain in the "very unhealthy" range of 201-300 and may even go above 300 into "hazardous" territory, it said.