A child looks at window cleaners work while dressed in sheep (C) and monkey costumes, denoting animal signs of the Chinese zodiac calendar, during an event marking the upcoming end of the year at a hotel in Tokyo, Japan, December 21, 2015. According to the zodiac calendar, 2015 is the year of the sheep and 2016 is the year of the monkey. (Photo by Thomas Peter/Reuters)

Growing cities, overuse of fertilizers and factory wastewater have degraded China's water supplies to the extent that half the nation's rivers and lakes are severely polluted. China aims to spend $850 billion to improve filthy water supplies over the next decade, but even such huge outlays may do little to reverse damage caused by decades of pollution and overuse in Beijing's push for rapid economic growth. Photo: Fishermen row a boat in the algae-filled Chaohu Lake in Hefei, Anhui province, June 19, 2009. (Photo by Jianan Yu/Reuters)

A huge wave crashes against Castlerock pier as professional surfer Al Mennie waits on a break in the swell on December 22, 2016 in Coleraine, Northern Ireland. Storm Barbara is expected to cause major travel disruption when it hits northern parts of the UK later with 90mph winds predicted. The Met Office has issued an amber warning with the worst effects of the storm expected on Friday and Saturday. (Photo by Charles McQuillan/Getty Images)

A rescue helicopter is shown at the Mount Everest south base camp in Nepal a day after a huge earthquake-caused avalanche killed at least 17 people, in this photo courtesy of 6summitschallenge.com taken on April 26, 2015 and released on April 27, 2015. Rescue teams, helped by clear weather, used helicopters to airlift scores of people stranded at higher altitudes, two at a time. (Photo by Reuters/6summitschallenge.com)

A woman raises her fist during events to mark Juneteenth, which commemorates the end of slavery in Texas, two years after the 1863 Emancipation Proclamation freed slaves elsewhere in the United States, amid nationwide protests against racial inequality, in the Harlem neighbourhood of Manhattan, in New York City, New York, June 19, 2020. (Photo by Andrew Kelly/Reuters)

Belarusian women take a selfie as they take part in the Mrs and Miss Minsk city pageant, amid the coronavirus disease (COVID-19) outbreak in Minsk, Belarus on June 26, 2020. (Photo by Vasily Fedosenko/Reuters)

Pedestrians look at the wreckage of a vehicle lodged in a storm drain on a street in Abidjan on June 19, 2018, in which a man was reportedly found dead after floodwaters receded following an overnight downpour in the city. Fifteen people have died in Abidjan, Ivory Coast' s economic capital, during flooding caused by torrential rain overnight, Interior Minister Sidiki Diakite said. Rain poured down overnight on June 19, causing flash floods up to 2.5 metres (more than eight feet) deep, he said. (Photo by Sia Kambou/AFP Photo)

A bride waits to take her wedding vow during a mass marriage ceremony in which, according to its organisers, 111 Muslim couples took their wedding vows, in Ahmedabad, India January 26, 2017. (Photo by Amit Dave/Reuters)