A model waits to present a creation by Chinese designer Hu Sheguang for his collection show during China Fashion Week S/S 2016 in Beijing October 26, 2015. (Photo by Jason Lee/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)

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)

Models Felicia Verna and Crystal Boyd wearing Stacey Angela during the Fallen Hearts Fashion Experience at Symphony Space on May 31, 2011 in New York City. (Photo by Jemal Countess/Getty Images)

Model presents a creation from the Agua de Coco por Liana Thomaz collection during the Sao Paulo Fashion Week in Sao Paulo, Brazil on April 21, 2018. (Photo by Nacho Doce/Reuters)

Bella Hadid, Vittoria Ceretti and Gigi Hadid are seen backstage ahead of the Alberta Ferretti show during Milan Fashion Week Spring/Summer 2018 on September 20, 2017 in Milan, Italy. (Photo by WWD/Rex Features/Shutterstock)

Models prepare themselves backstage ahead of the International Dwarf Fashion Show, on September 26, 2017 in Paris, France. (Photo by Thomas Samson/AFP Photo)

A model presents a creation by designer Katy Nguyen during Vietnam International Fashion Week in Hanoi, Vietnam, Wednesday, November 1, 2017. (Photo by Hau Dinh/AP Photo)