A Yemeni pro-government fighter is pictured during fighting with Huthi rebels on the south frontline of Marib, the last remaining government stronghold in northern Yemen, on November 10, 2021. A Yemeni military official said that 28 fighters from the pro-government Obaida tribe and seven government forces were killed in clashes with rebels south of Marib over the previous 24 hours. (Photo by AFP Photo/Stringer)

A pedestrian wearing a face mask to protect against coronavirus, walks in front of a mural, at a metro station in Athens, Greece, Monday, November 15, 2021. Authorities say the rate of death related to COVID-19 in Greece has reached its highest level in six months as roughly one-third of the country's population remains unvaccinated. (Photo by Thanassis Stavrakis/AP Photo)

Natalia Lage Rainha de Drums of the Escola de Samba Inocente de Belford Roxo during a presentation in the parade of the Special Group of Carnival in Rio de Janeiro at Avenida Marques de Sapucai, Sambadrome in Rio de Janeiro on April 21, 2021. The Carnival parades that take place in February were postponed to this month of April due to the high number of cases caused during the pandemic caused by COVID-19 (Coronavirus). (Photo by Thiago Ribeiro/AGIF via AFP Photo)

People search for shells on a beach in Sittwe, Rakhine State, Myanmar, 17 September 2020. International Coastal Cleanup Day is observed annually on the third Saturday of September and will occur on 19 September this year. (Photo by Nyunt Win/EPA/EFE/Rex Features/Shutterstock)

South Korean environmentalists participates in a rally held to commemorate the Fukushima nuclear disaster on the eve of the one year anniversary of Japan's earthquake and tsunami on March 10, 2012 in Seoul, South Korea. Currently four nuclear power plants are in operation in South Korea while the government plans to increase the number of reactors to 32 by the year 2021. (Photo by Chung Sung-Jun/Getty Images)

Lance Sergent Martin Mitchell (R) pins medals to Coldstream Guardsman Martin Hughes in the Tailor Shop in Wellington Barracks on April 20, 2011 in London, England. Soldiers involved in the Royal Wedding of Prince William and Catherine Middleton are preparing their ceremonial duties ahead of the day. (Photo by Oli Scarff/Getty Images)

A protester uses molotov cocktails against riot police during May Day protests on May 1, 2010 in Athens, Greece. (Photo by Milos Bicanski /Getty Images)

Charlene Wittstock (L) and Prince Albert II of Monaco (R) attend the singles Final match between Rafael Nadal of Spain and Roger Federer of Switzerland on day nine of the Monte Carlo Masters Series tennis tournament. (Photo by Pascal Le Segretain/Getty Images). 2008