Sri Lanka, Dec. 12 -- The ambient air quality status in most of the urban areas showed an improvement yesterday, the National Building Research Organisation (NBRO) said.

The dynamic air quality with respect to PM2.5 (particles less than 2.5 micrometers in diameter) remained at the levels of "moderate" and "unhealthy for sensitive groups" in most of the cities yesterday afternoon, according to the data of the Real-Time Air Quality Monitoring Unit of the NBRO.

"The Air Quality Index level for Saturday (24-hour average) indicated an "unhealthy level" (this category means that "everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects") in Kegalle, while it was "unhealthy for sen...