Construction workers are seen in heavy dust in Iran's Sarpol-e Zahab city on Oct. 27, 2018. Heavy sand storm engulfed some western cities of Iran on Saturday. (Xinhua/Ahmad Halabisaz)

People walk on a street in heavy dust in Iran's Sarpol-e Zahab city on Oct. 27, 2018. Heavy sand storm engulfed some western cities of Iran on Saturday. (Xinhua/Ahmad Halabisaz)