An aerial view shows a sinkhole 3.5 km (2 miles) to the east of Solikamsk-2 mine in Perm region, November 20, 2014. Shares in Russia's Uralkali, the world's top potash producer, fell sharply for a second day on Wednesday after a mine accident that could reduce global supplies and push up prices of the crop nutrient worldwide. Uralkali shares have fallen 28 percent since Tuesday when it suspended work at its Solikamsk-2 mine, which accounts for a fifth of the company's output and 3.5 percent of global capacity, following an inflow of water. A sinkhole, stretching 30 by 40 metres (yards), found at an abandoned mine 3.5 km (2 miles) to the east, increased concern about the future of the mine because an inflow of water and the resulting sinkhole in 2006 forced another Uralkali operation to shut permanently. (Photo by Reuters/Press service of Uralkali company)

Pedestrians cover their face as they walk along the dusty road in Kathmandu, Nepal February 27, 2017. Nepal has forced 2,500 old vehicles off roads in its capital city of Kathmandu, part of a fight against alarming air pollution levels that have hit nine times World Health Organisation (WHO) limits. Air pollution has been a chronic problem in rapidly growing Kathmandu, which sits in a Himalayan valley and is home to more than 3mn people. (Photo by Navesh Chitrakar/Reuters)

A boy holds his mother's leg as he cries in front of their damaged house after a strong 6.6 magnitude earthquake at Longmen village, Lushan county in Ya'an, Sichuan province. (Photo by Jason Lee/Reuters)

Head of European Prints, Severine Nackers holds a celestial Map of the Southern Sky by Albrecht Durer, at Sotheby's Auction House on March 25, 2011 in London, England. The two woodcut maps depicting the Northern and Southern skies circa 1515, are the earliest printed star charts of their kind ever published in Europe, and are expected to fetch between Ј120,000-180,000 GBP when they go on sale at the “London sale of Old Master, Modern and Contemporary prints” at Sotheby's Auction house on March 30, 2011. (Photo by Dan Kitwood/Getty Images)

The villas of Marabe Al Dhafra in Abu Dhabi, United Arab Emirates are home to approximately 2,000 people. Located in one of the hottest regions of the world, the record high temperature here is 49.2C° (120.6F°). (Photo by Benjamin Grant/Penguin Random House)

Members of the University of Maryland women's lacrosse team react to something Trump said after posing for photographs during an event with NCAA championship teams at the White House on November 17, 2017. (Photo by Jabin Botsford/The Washington Post)

Storks that were saved by Bulgarian farmer Safet Ismail are pictured in the village of Zaritsa, Bulgaria, March 21, 2018. Dozens of people from villages in north-eastern Bulgaria took storks to their houses as a lot of the birds got injured due to freezing temperatures and snowfalls in the area over the last few days. (Photo by Stoyan Nenov/Reuters)

Mural of wartime leader Sir Winston Churchill wearing stockings and suspenders and giving the “V” sign by illusive local artist who goes by the name Horace, on the side of the Sandpiper guest house in Brighton on November 22, 2020. (Photo by Gareth Fuller/PA Images via Getty Images)