Masks have become a necessity for people who live in smog-ravaged areas. Let's have a look at how sport fans arm themselves to cheer for their teams.
![Cheer in masks](../../images/attachement/jpg/site1/20131210/0013729e42d21410ceb108.jpg) |
Fans of the St Louis Cardinals wear masks to cheer for their baseball team in June, 2013, St Louis, US. [Photo/icpress.cn]
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