COLOMBO, Nov.
11 (Xinhua) -- Sri Lanka's air quality is soon returning to normal as the air quality index has reached moderate levels from above 100 recorded last week, the state owned National Building Research Organization (NBRO) said here Monday.Senior Scientist at the NBRO, Sarath Premasiri told Xinhua that the air quality index over the island had lowered to a moderate 60 to 70 by the weekend from the above 100 recorded last week and it no longer posed a health risk on the citizens.