A migrant labourer brushes his teeth in front of a scrapped helicopter model in Mumbai, India, April 13, 2016. (Photo by Danish Siddiqui/Reuters)

Tattoo artists work on clients during the second International Tattoo Festival in Sochi, Russia, April 23, 2016. (Photo by Kazbek Basayev/Reuters)

Kendall Jenner and Kylie Jenner seen in this celebrity social media picture on September 1, 2016. (Photo by XposurePhotos.com)

Women perform yoga on a dried river bank in Yunyang county, Chongqing Municipality, August 21, 2016. (Photo by Reuters/China Daily)

Early morning storms over the Masai Mara National Reserve, Kenya on August 26, 2016. (Photo by Action Press/Rex Features/Shutterstock)

Security personnel patrol around West Lake in Hangzhou, Zhejiang Province, China, August 31, 2016. (Photo by Reuters/Stringer)

A dog jumps into the pool during the Flying Dogs competition in Kamnik, Slovenia, September 10, 2016. (Photo by Srdjan Zivulovic/Reuters)

Serbian police officers of the Special Anti-Terrorist Unit pose for a picture in their base outside Belgrade October 8, 2014. When the killing of an unarmed black teenager by a white policeman in Ferguson, Missouri, in August sparked sometimes violent protests, the response of police in camouflage gear and armoured vehicles wielding stun grenades and assault rifles seemed more like a combat operation than a public order measure. Some U.S. police departments have recently acquired U.S. military-surplus hardware from wars abroad, but there are many law enforcers around the world whose rules of engagement also allow the use of lethal force with relatively few restrictions. But for every regulation that gives police wide scope to use firearms, there is another code that sharply limits their use. In Serbia, police may use measures ranging from batons to special vehicles, water cannon and tear gas on groups of people who have gathered illegally and are behaving in a way that is violent or could cause violence, but they may use firearms only when life is endangered. (Photo by Marko Djurica/Reuters)