A Chhattisgarh government agency has accused the National Highways Authority of India (NHAI), engaged in the construction of Raipur-Bilaspur highway, of violating air pollution control norms. The Chhattisgarh Environment Conservation Board (CECB) has served a notice to the project director of the NHAI for allegedly violating air pollution norms while constructing the four-lane highway connecting the two key cities. Taking cognisance of dust pollution caused during the four-laning work of the road, the CECB issued a notice to the project director of the NHAI yesterday seeking a reply within 15 days, a board official said today. In the notice, the CECB has sought to know why strong action should not be taken against the agency under the Air (Prevention & Control of Pollution) Act for not controlling dust during the construction and why the four-laning work should not be stopped, he said. The board has asked construction agencies in Bilaspur to sprinkle water at the construction sites and the municipal corporation to do a similar thing on roads so as to prevent dust pollution, he added. Similar notices have also been served to authorities involved in upgradation of nearly half a dozen roads in the state capital, the official said.