An airplane is silhouetted at sunrise, seen from the suburb of Saint-Cloud, near Paris, France, 08 December 2016. Paris is undergoing a third day pollution spike, prompting the city to limit vehicle circulation. (Photo by Ian Langsdon/EPA)

Anti-pollution protesters wearing traditional costumes and contemporary gas masks ride bicycles in the Qingming Grand river park in Kaifeng, Henan Province, China on January 1, 2017. The Beijing Municipal Environmental Protection Bureau extended an “orange alert” for heavy air pollution for three more days. (Photo by SIPA Asia/Rex Features/Shutterstock)

A dancer waits to perform during festivities marking the start of the annual harvest festival of “Onam” in Kochi, India, August 19, 2015. The ten-day-long Hindu festival is celebrated annually in India's southern coastal state of Kerala to commemorate the return of King Mahabali to his beloved subjects. (Photo by Sivaram V/Reuters)

Iraqi troops fire artillery towards Islamic State (IS) group jihadists' positions in west Mosul on March 11, 2017 during the ongoing battle to retake the city from the group. (Photo by Aris Messinis/AFP Photo)

A Hindu holy man on his way to the annual holy dip at Gangasagar, gestures towards a visitor as he rests at a transit camp in Kolkata, India, Wednesday, January 6, 2016. Thousands of Hindu pilgrims are expected to take the annual holy dip at Gangasagar, where the Ganges River reaches the Bay of Bengal, on the auspicious Makar Sankranti festival day that falls on Jan.14. (Photo by Bikas Das/AP Photo)

Two female revelers engage in a beer drinking contest in the Hacker Pschorr tent on the first day of the 2017 Oktoberfest beer fest on September 16, 2017 in Munich, Germany. Oktoberfest is the world's largest beer celebration and typically draws over six million visitors over its three-week run. Oktoberfest includes massive beer tents, each run by a different Bavarian brewer, as well as amusement rides and activities. (Photo by Philipp Guelland/Getty Images)

A Los Angeles County Fire helicopter flies over during the “Skirball Fire” which began early morning in Bel-Air, California, USA, 06 December 2017. An outbreak of several fires North of Los Angeles has occurred as one of the strongest Santa Ana winds forecast of the season is ongoing and expected to last several days. (Photo by John Cetrino/EPA/EFE)

Visitors look at tropical fish transported from Japan's southern island of Okinawa displayed in a giant 14-ton fish tank at the Sony Square event space in Tokyo on July 17, 2016. The 45-day-long summer exhibition will be held through August 28 to display sea creatures common to the waters around Okinawa. (Photo by Kazuhiro Nogi/AFP Photo)