Canned clean air is handed out to participants in a tree planting event in Xi’an City, capital of Northwest China’s Shaanxi Province, March 10, 2017. The air, collected deep in the Qinling Mountains and said to be oxygen-rich, was compressed in order to store it in a canister. One canister has seven liters of air and sells at 18 yuan ($2.6). (Photo/CFP)
