Demonstrators wear masks depicting Brazil's former president Luiz Inacio Lula da Silva (R) and Brazil's President Dilma Rousseff (L) as they take part in a protest calling for the impeachment of Rousseff at Paulista Avenue in Sao Paulo, Brazil, December 13, 2015. (Photo by Nacho Doce/Reuters)

A woman smokes a cigarette next to man wearing a mask during lunch hour at the central business district in Singapore September 29, 2015. The 3-hour haze Pollutant Standards Index (PSI) reached a high of 173 at 8am on Tuesday, according to the National Environment Agency. Slash-and-burn agriculture in neighboring Indonesia has blanketed Singapore in a choking haze for weeks. (Photo by Edgar Su/Reuters)

Men wearing masks and dressed as military members take part in a festival honouring San Silvestre, in the town of Catarina, Nicaragua January 1, 2016. The placard reads, “I'm not afraid, young people off the streets, Ortega you sell our country”, in reference Nicaragua's President Daniel Ortega. (Photo by Oswaldo Rivas/Reuters)

In this July 11, 2016 photo, a young, masked drug trafficker poses for photos holding his guns at a slum in Rio de Janeiro, Brazil. Teenagers openly tote guns while they work as guards, lookouts and distributors for drug lords operating just a few miles from where hundreds of thousands and tourists and athletes will be for the Aug. 5-21 Olympic Games. (Photo by Felipe Dana/AP Photo)

A masked Burundian protester faces soldiers in front of a burning barricade during an anti-government demonstration against President Pierre Nkurunziza's bid for a third term in the capital Bujumbura, Burundi, 25 May 2015. Street protests continued on 25 May as the United Nations Secretary-General Ban Ki-moon condemned the killing of the leader of the oppsition party Union for Peace and Development (UPD) Zedi Feruzi who opposed Nkurunziza's bid. (Photo by Dai Kurokawa/EPA)

A policewoman tries to stop an anti-Occupy protester from breaking a police cordon to charge at pro-democracy protesters during a confrontation in Hong Kong October 13, 2014. Hundreds of unidentified people, some wearing masks, tried to break down protest barriers in the heart of Hong Kong's business district on Monday, scuffling with protesters who have occupied the streets for the past two weeks. (Photo by Bobby Yip/Reuters)

Members of Japan's idol group “Virtual Currency Girls” wearing cryptocurrency-themed masks perform in their debut stage in Tokyo, Japan, January 12, 2018. Japanese female idols have teamed up to form the ‘Virtual Currency Girls’ group to promote the knowledge of cryptocurrencies through entertainment. Each of its 8 members represents a cryptocurrency: bitcoin cash, bitcoin, ether, neo, nem, ripple, mona, and cardano. (Photo by Kim Kyung-Hoon/Reuters)

In this January 29, 2017 photo, musicians perform for dancers on the shores of Lake Titicaca, as they practice before their presentation for the Virgin of Candelaria celebrations in Puno, Peru. Dancers in colorful masks and elaborate costume celebrate the Virgin of Candelaria, patron saint of communities along the shore of Lake Titicaca, in what's considered the largest Catholic festival in the Andes. (Photo by Rodrigo Abd/AP Photo)