Models painted in camouflage colours to blend in with the background pose for Chinese artist Liu Bolin's artwork “Dongji”, or Winter Solstice, on the second day after China's capital Beijing issued its second ever “red alert” for air pollution, in Beijing, China, December 20, 2015. In this artwork, Liu wants to express his concerns about China and its people, including air pollution problem, Liu told Reuters. (Photo by Kim Kyung-Hoon/Reuters)

In this April 28, 2015 file photo, heads of tuna on a cart are carried by a fish dealer after the day's auction at Tsukiji Wholesale Market in Tokyo. In one of the biggest of Japan's many New Year holiday rituals, early on Tuesday, January 5, 2016, Tokyo's Tsukiji market will auction off with much fanfare a huge, glistening tuna, likely destined for one of the big sushi chains. If all goes as planned, it will be the last such auction at 80-year-old Tsukiji. (Photo by Shuji Kajiyama/AP Photo)

A dramatic rise in owning exotic pets in China is fuelling global demand for threatened species. The growing trade in alligators, snakes, monkeys, crocodiles and spiders is directly linked to species loss in some of the world’s most threatened ecosystems. Here: A fennec fox (Vulpes zerda) is groomed in a pet store in central Beijing. Native to the Sahara in North Africa, the species became a popular pet after being depicted as a character in Disney’s 2016 animated movie Zootopia. Individuals can cost between $2,000–$3,000. (Photo by Sean Gallagher/The Guardian)

A cat tries to find dry ground around an apartment complex in Houston after Hurricane Harvey hit on Aug. 30. Harvey made landfall in South Texas on August 25, leading to days of downpours that dumped more than 50 inches of rain. Harvey damaged or destroyed about 200,000 homes as the storm system flooded much of Houston and smaller coastal communities. (Photo by Scott Olson/Getty Images)

In this November 30, 2017 photo, Douglas scoops up mud from the bottom of the polluted Guaire River, in search of gold and anything valuable he can sell, in Caracas, Venezuela. Some stretches of the river smell of sewer while others emit a toxic odor of fuel, a stench that stays in ones nose for hours after leaving the water. (Photo by Ariana Cubillos/AP Photo)

One of four Acehnese teen gets whipped for spending time in close proximity with her boyfriend who is not her husband, which is against Sharia law, in Aceh on April 18, 2017. Aceh on Sumatra island began implementing Sharia law after being granted special autonomy in 2001, an attempt by the central government in Jakarta to quell a long-running separatist insurgency. (Photo by Chaideer Mahyuddin/AFP Photo)

Villagers look on as Mount Sinabung volcano spews thick volcanic ash, as seen from Beganding village in Karo, North Sumatra province, on May 19, 2017. Sinabung roared back to life in 2010 for the first time in 400 years. After another period of inactivity, it erupted once more in 2013 and has remained highly active since. (Photo by Ivan Damanik/AFP Photo)

In this June 12, 2017 photo, a woman stands in front of a mural on the slope in Central district, Hong Kong. Once known as Victoria after the British queen, Hong Kong island's waterfront formed the core of the British settlement after Hong Kong island was handed over as a colony in 1842. Today as Hong Kong approaches the 20th anniversary of its return to China, it remains a bustling commercial and financial center as well as the location of the main government offices. However, along the streets that angle sharply upward toward the mountains above, a more relaxed pace of life endures. (AP Photo/Kin Cheung)