This picture taken on January 25, 2015 shows a participant taking part in an ice water challenge in Zhangjiajie, central China's Hunan province. Participants were required to stay in an ice pond, holding an ice block while eating ice-cream with an electric fan blowing at them. (Photo by AFP Photo/Stringer)

In this photo taken on Sunday, July 5, 2015, police officers walk along a giant poster to give an improved appearance, in downtown Ufa, Russia. Ufa will host SOC (Shanghai Cooperation Organization) and BRICS (Brazil, Russia, India, China and South Africa) summits July 7 to July 9, 2015. (Photo by Vadim Braydov/AP Photo)

An explosion at a petrochemical plant is seen in Rizhao, Shandong province, July 16, 2015. According to Xinhua News Agency, a fire broke out after the explosion, which was caused by a liquified hydrocarbon leak at the plant, on Thursday morning. There was no report of casualties yet. (Photo by Reuters/China Daily)

Children eat watermelons to meet the “beginning of autumn” at a kindergarten in Handan, China on August 7, 2015. Chinese tradition to eat watermelons or peaches before that day symbolises “biting away summer”. The solar term ‘beginning of autumn’ falls on 8 August this year. (Photo by Xinhua/REX Shutterstock)

A combination of pictures shows people taking photos of themselves in Tiananmen Square as they celebrate National Day marking the 67th anniversary of the founding of the People's Republic of China, in Beijing October 1, 2016. (Photo by Damir Sagolj/Reuters)

Aerobatic aircrafts fly during a performance at the Airshow Zhengzhou 2017 in Zhengzhou, capital of central China's Henan Province on April 27, 2017. The 5-day air show kicked off in Zhengzhou on Thursday, aiming to build a general aviation gathering center for business and communications. (Photo by Li An/Xinhua via ZUMA Wire)

The manager of Jinhua Partytime Latex Art and Crafts Factory wears a mask of U S. Democratic presidential candidate Bernie Sanders as he poses and gives a thumbs-up as during a presentation of products to reporters at his factory's showroom in Jinhua, Zhejiang Province, China, May 25, 2016. (Photo by Aly Song/Reuters)

Children are engulfed by foam during the Bubble Show event in Beijing, China, Sunday, June 26, 2016. Thousands of residents enjoy colored foam churned out by machines along a running track at the event designed for children and parents' interaction. (Photo by Ng Han Guan/AP Photo)