A women wearing a mask to protect from extreme smog visits the Tiananmen Gate in Beijing December 8, 2015 as China's capital issues its first ever "red alert" for pollution. (Photo by Damir Sagolj/Reuters)

A model waits backstage before the Spring/Summer 2017 Fashion Palette show at New York Fashion Week in Manhattan, New York, U.S., September 8, 2016. (Photo by Andrew Kelly/Reuters)

Models wear creations by brand Leonisa during Colombiamoda fashion event in Medellin, Colombia, July 28, 2015. (Photo by Fredy Builes/Reuters)

A model presents a creation by Paradizia during Colombiamoda fashion event in Medellin, Colombia, July 29, 2015. (Photo by Fredy Builes/Reuters)

(L-R) Poppy Delevingne, Model of the Year Cara Delevingne, Joan Smalls and Karlie Kloss pose in the winners room at the British Fashion Awards at London Coliseum on December 1, 2014 in London, England. (Photo by Pascal Le Segretain/Getty Images)

A model poses backstage at the Topshop Unique catwalk show during London Fashion Week in London, Britain February 19, 2017. (Photo by Neil Hall/Reuters)

A model presents a creation by Chinese designer Chen Wen at China Fashion Week in Beijing, China March 29, 2017. (Photo by Jason Lee/Reuters)

A model presents a creation of Peruvian designer Ani Alvarez Calderon during Fashion Week in Lima, Peru, April 25, 2017. (Photo by Guadalupe Pardo/Reuters)