Chinese government ordered more than 1,200 factories, including an oil refinery plant of China Petroleum and Chemical Corporation to either suspend or cut output after earlier issuing this year's first red alert warning for severely high levels of air pollution. 
Under a contingency plan for severe air pollution, the city shut down more than 700 plants with production procedures that will pollute air and required 500 more to reduce production. 
Beijing strengthened emergency measures after the alert was issued on Thursday to restrict vehicle usage in an effort to help clear the air. As part of the plan, vehicles considered the worst offenders are restricted from the roads when orange and red alerts are in place.

Source: QNA