The haze in Singapore eased slightly at noon on Tuesday, with the three-hour Pollutant Standards Index (PSI) dipping to 114 at noon, down from 123 an hour ago.
But air quality remained in the unhealthy range, which is anything over 100.
The 24-hour average concentration of PM2.5, or very fine particulate matter, was between 154 and 186 micrograms per cubic metre at noon, a rise from 145-179 at 8am. The 24-hour reading measures fine pollutants, which are more hazardous because they can enter the lungs or bloodstream more easily than larger dust particles.
The National Environment Agency has advised that people with heart or lung disease, children and older adults should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion.