This picture taken on September 9, 2014 shows a waiteress handing over food to customers at a prison themed restaurant in Tianjin. As more themed restaurants are popular in China, a “prison style” restaurent in Tianjin is aimed at reminding people to observe the law and to be good citizens. (Photo by Wang Zhao/AFP Photo)

Chinese special policemen rank in a line of battle during an anti-terror drill at a training base of Chengdu Armed Police Headquarters on September 28, 2005 in Chengdu of Sichuan Province, China. (Photo by China Photos/Getty Images)

A citizen rides in smog on December 20, 2016 in Jinan, Shandong Province of China. Air quality index (AQI) readings exceeded 400 and some schools have suspended classes in Jinan. (Photo by VCG/VCG via Getty Images)

A woman walks up the steps decorated ahead of the Chinese New Year festival in Beijing, China, Thursday, January 12, 2017. The Chinese Lunar New Year is the most important holiday for Chinese and hundreds of millions are expected to return to their hometown to spend the new year with their family and relatives. (Photo by Ng Han Guan/AP Photo)

Participants dressed as characters such as elves, dwarves, goblins and orcs from the J.R.R. Tolkien's novel “The Hobbit” re-enact the “Battle of Five Armies” in a forest near the town of Doksy, Czech Republic, June 4, 2016. Several hundred people arrived in the forest to re-enact the famous battle from Tolkien's novel that was published for the first time in 1937. (Photo by David W. Cerny/Reuters)

Deshauna Barber (C) of the District of Columbia poses with other contestants after being crowned Miss USA 2016 during the 2016 Miss USA pageant at the T-Mobile Arena in Las Vegas, Nevada, U.S., June 5, 2016. (Photo by Steve Marcus/Reuters)

Britain Horse Racing, Royal Ascot, Ascot Racecourse on June 14, 2016. Racegoers in Britain and EU referendum themed dresses. (Photo by Toby Melville/Reuters/Livepic)

A machine works on a Rio 2016 Olympic medal at the Casa da Moeda do Brasil (Brazilian Mint) in Rio de Janeiro, Brazil, June 28, 2016. The Casa da Moeda do Brasil is the Brazilian mint, owned by the Brazilian government and administratively subordinated to the Ministry of Finances. It was established in 1694. (Photo by Sergio Moraes/Reuters)