A woman wears a face mask on a hazy January day in downtown Shanghai. China has ordered a popular anti-pollution film removed from major online outlets. In Xi'an, two people who had protested against smog were reportedly detained. ALY SONG/Reuters /Landov hide caption
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Environmental Protection Agency Administrator Gina McCarthy testifies at an oversight hearing of the Senate Environment and Public Works Committee on Capitol Hill in Washington on July 23. J. Scott Applewhite/AP hide caption
Tourists from mainland China take photos in front of a large outdoor banner showing what Hong Kong looks like on a clean air day, in Hong Kong on Aug. 21. Alex Hofford/EPA/Landov hide caption
The sun rises over the Singapore Central Business District as smog shrouds the city-state on Thursday. Joseph Nair/AP hide caption