COLOMBO, Nov. 7 (Xinhua) -- Sri Lanka's state owned Central Environmental Authority on Thursday informed the World Health Organization (WHO) to examine the reasons for the unusual rise of dust concentration in the air across the country, local media reported.

Deputy Director General of the Central Environmental Authority, K.H.M. Aarachchi said that they had also informed the Meteorology Department to probe as to what had caused dust particles to increase in the air since late Tuesday.

On Wednesday, Sri Lanka's air quality reached cautionary levels as the Air Quality Index (AQI) hit 112 by afternoon, reaching far above the normal levels, the National Building and Research Organization (NBRO) said.

Sarath Premasiri, senior scientist at the Environmental Studies Unit of NBRO, was quoted by local media as saying that on Wednesday morning the AQI levels in several parts of the country reached 173 and declined to 165 by noon.

The standard level of AQI is measured at around 50 or below.

Premasiri said the prevailing severe air pollution in New Delhi, India may have been one of the causes but added investigations were ongoing to ascertain all the causes for the air pollution prevailing in the island country.