An Iranian woman wearing a protective mask walks on a street in downtown Tehran, Iran, on Dec. 4, 2012. Iran’s government has announced that all government offices, universities and schools of Tehran closed for two days, Dec. 4 and 5, due to the alarming high air pollution in the city.
A view of Tehran covering in dust is seen on Dec. 4, 2012. <Xinhua/Ahmad Halabisaz>
