PSI hits unhealthy level with high concentration of ozone in northern Singapore as 12 imported Coivd-19 cases reported

Healthy people are urged to reduce prolonged or strenuous outdoor physical exertion. - The Straits Times/ANN

SINGAPORE, March 28 (The Straits Times/ANN): Air quality hit unhealthy levels again in the northern parts of Singapore on Sunday evening, because of high concentrations of ozone, according to the National Environment Agency's (NEA) website.

At 8pm, the Pollutant Standards Index (PSI) reading stood at 114, in the unhealthy range, though it returned to the moderate range at 9pm, with the PSI dropping to 97.