A visitor holds an Israeli-made rifle during the 8th International Land and Naval Defense system exhibition, in New Delhi, India, on February 6, 2014. (Photo by Anindito Mukherjee/Reuters)

A member of the mainly Christian “anti-balaka” (anti-machete) militia trains in the Boeing neighbourhood of Bangui, Central African Republic, on February 24, 2014. (Photo by Fred Dufour/AFP Photo)

A narrow strip of clouds illuminated in the light of sunset before approaching rain clouds over an alley near Sieversdorf district Oder-Spree, Brandenburg, Germany on July 14, 2016. (Photo by Patrick Pleul/DPA)

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)

This August 28, 2017 photo shows eight-year-old Indian girl Bharti performing a balancing act on a rope during a street show in Batala, India. Travelling Indian performers, who earn a meagre income from putting on shows on the streets, often scout areas to gather a large street audience who then give money on a collection plate at the end of the show. (Photo by Narinder Nanu/AFP Photo)

A model presents a creation during a hair styling competition in Minsk, Belarus on November 9, 2017. (Photo by Sergei Gapon/AFP Photo)

A model walks the runway during the Di$count Universe show at Mercedes-Benz Fashion Week Resort 17 Collections at Carriageworks on May 18, 2016 in Sydney, Australia. (Photo by Stefan Gosatti/Getty Images)

Indian men stand around sword fish for sale at a harbour a harbour in Chennai on June 5, 2016, as fishermen return with their catch after a 45-day fishing ban on the east coast of India. Authorities in the southern Indian state of Tamil Nadu had imposed a 45-day ban on fishing by mechanised vessels to protect marine life, with only “country boats” operating within five nautical miles off the coast. (Photo by Arun Sankar/AFP Photo)