A picture made available 16 December 2016 shows a woman taking photos of lion sculptures that have their mouth covered by masks, on top of the stone hitching posts in Xi'an Fine Art College in Xi'an, Shaanxi province, China, 12 December 2016. Several art students spent an hour and a half in the night to putting masks on more than 800 stone hitching posts to raise awareness of air pollution. (Photo by EPA/Stringer)
