Pedestrians wear masks as smoke and haze from bushfires in New South Wales blankets the CBD in Sydney, Australia, 10 December 2019. The New South Wales environment department says visibility across east and southwest Sydney was at a “hazardous” level on Tuesday morning, while air quality was poor in southwest Sydney and hazardous in northwest Sydney. (Photo by Steven Saphore/EPA/EFE)

A woman takes a selfie next to a model of Thor during the Middle East Film & Comic Con (MEFCC) in Dubai, United Arab Emirates, Saturday, April 11, 2015. (Photo by Kamran Jebreili/AP Photo)

People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)

A youth dives into a crater filled with water in Aleppo's al-Shaar district, in this July 10, 2014 file photo. (Photo by Hosam Katan/Reuters)

Supporters of the presidential candidate Muhammadu Buhari and his All Progressive Congress hits another supporter with a motorbike during celebrations in Kano, Nigeria March 31, 2015. (Photo by Goran Tomasevic/Reuters)

Prime Minister Theresa May meets Russian President Vladimir Putin during the G20 summit in Osaka, Japan on June 28, 2019. (Photo by Stefan Rousseau/PA Images via Getty Images)

Traditional dancers from southern state Tamil Nadu prepare themselves as they wait to perform during a press preview of displays being featured for the upcoming Republic Day parade in New Delhi on January 22, 2019. The Republic Day is an annual showcase of India's military hardware and cultural diversity. India celebrates its 70th Republic Day on January 26. (Photo by Sajjad Hussain/AFP Photo)

A belly dancer performs in a talent show in early morning ceremonies for Groundhog Day on February 2, 2018 in Punxsutawney, Pennsylvania. Punxsutawney Phil, the weather-forecasting groundhog, emerged from his burrow in Pennsylvania on Friday, saw his shadow and predicted six more weeks of winter, despite his rival Staten Island Chuck in New York predicting an early spring. (Photo by Brett Carlsen/Getty Images)