Riot police detain a woman during a protest near Mong Kok police station in Hong Kong, China on September 7, 2019. (Photo by Tyrone Siu/Reuters)

Russian cosmonaut Alexander Skvortsov, Expedition 40 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of science and maintenance on the International Space Station on August 18, 2014. During the five-hour, 11-minute spacewalk, Skvortsov and cosmonaut Oleg Artemyev (out of frame) deployed a small science satellite, retrieved and installed experiment packages and inspected components on the exterior of the orbital laboratory. (Photo by NASA)

Children of the Roma community play as they cool off in a fountain in the main square of Pristina, Kosovo on June 14, 2017. (Photo by Armend Nimani/AFP Photo)

Traditional dancers are seen at Ela Beach, near a venue of the Asia-Pacific Economic Cooperation (APEC) summit in Port Moresby, Papua New Guinea, 13 November 2018. The APEC summit brings together world leaders from its 21 member nations and is being hosted for the first time by Papua New Guinea. (Photo by Mast Irham/EPA/EFE)

A devotee of Hindu goddess Kali performs a ritual during the “Bonalu” festival in Hyderabad, India, Sunday, July 28, 2019. Bonalu is a month-long Hindu folk festival of the Telangana region dedicated to Kali, the Hindu goddess of destruction. (Photo by Mahesh Kumar A./AP Photo)

A devotee participates in Holi celebrations at the Nandagram temple, on March 22, 2013. (Photo by Manish Swarup/Associated Press)

A devotee of the Chinese shrine of Kathu Shrine, pierces his cheeks with umbrellas during a procession of Vegetarian Festival on October 4, 2011 in Phuket, Thailand. Ritual Vegetarianism in Phuket Island traces it roots back to the early 1800's. The festival begins on the first evening of the ninth lunar month and lasts for nine days. Participants in the festival perform acts of body piercing as a means of shifting evil spirits from individuals onto themselves and bring the community good luck. (Photo by Athit Perawongmetha/Getty Images)

Widows, who have been abandoned by their families, light sparklers after offering prayers on the banks of the river Yamuna as part of Diwali celebrations organised by non-governmental organisation Sulabh International in Vrindavan, Uttar Pradesh October 21, 2014. (Photo by Ahmad Masood/Reuters)