People walk under Australia's iconic landmark Harbour Bridge in Sydney on April 3, 2019, as heavy fog blankets the city. Low visibility due to heavy fog affected traffic in the city and caused flight delays at the Sydney airport. (Photo by Saeed Khan/AFP Photo)

Anti-frost candles burn in apricot plantations to protect flowering buds and blossoms from frost in the midst of the Swiss Alps, in Saxon, Canton of Valais, Switzerland, 05 April 2019. With an unusually low temperature forecast for the season, fruit growers try to protect their buds from frost damage with two different means, icy water or large candles. (Photo by Valentin Flauraud/EPA/EFE)

In this photo taken on Sunday, March 10, 2019, a little girl laughs during a ritual marking the upcoming Clean Monday, the beginning of the Great Lent, 40 days ahead of Orthodox Easter, on the hills surrounding the village of Poplaca, in central Romania's Transylvania region. Romanian villagers burn piles of used tires then spin them in the Transylvanian hills in a ritual they believe will ward off evil spirits as they begin a period of 40 days of abstention, when Orthodox Christians cut out meat, fish, eggs, and dairy. (Photo by Vadim Ghirda/AP Photo)

View of the Villarrica volcano taken from Pucon, some 800 kilometres south of Santiago, showing signs of activity on December 06, 2017. (Photo by Christian Miranda/AFP Photo)

In this August 26, 2019 photo, children of the Nambikwara Sarare tribe climb trees as they play in their indigenous reserve in the southwestern Amazon, near Conquista D'Oeste, in the Brazilian state of Mato Grosso. About 98% of all Brazil’s indigenous lands lie within the Amazon. (Photo by Andre Penner/AP Photo)

A view of the Lakhta Center multifunctional complex under construction in St Petersburg' s Primorsky District and a cable stayed bridge of the Western High- Speed Diameter toll motorway in St Petersburg, Russia on March 5, 2018. (Photo by EPA/EFE/Rex Features/Shutterstock)

A morning fog is seen in the Siberian city of Omsk, Russia on October 8, 2019. (Photo by Alexey Malgavko/Reuters)

A great crested grebe feeds a chick sitting on its mother’s back on a lake in Cáceres, Spain. (Photo by Jose Luis Ruiz/Solent News & Photo Agency)