Vehicle lights illuminate a street after a massive blackout, in San Juan, Puerto Rico, Thursday, September 22, 2016. Puerto Ricans faced another night of darkness Thursday as crews slowly restored electricity a day after a fire at a power plant caused the aging utility grid to fail and blacked out the entire island. (Photo by Carlos Giusti/AP Photo)

A woman wearing a mask reacts at her garden which locates next to chimneys of coal-fired power plant in Shijiazhuang, Hebei province, China, January 28, 2015. Beijing introduced tougher regulations this year to combat pollution, keen to overhaul China's unwanted image of smog-choked cities, fouled waterways and heavy-metal tainted soil. (Photo by Kim Kyung-Hoon/Reuters)

Two styles of cleaned bird's nest, Yan Zhan (L) and Su Zhan (R) await repacking at a processing plant in Kuala Lumpur, February 17, 2015. Prized in China for is alleged health benefits for hundreds of years, nests made from swiftlets' saliva are being mixed into coffee and cereal as the Southeast Asian producers of the delicacy seek to broaden its appeal, and their profit margins. The nests are among the world's most expensive foods, selling for up to $2,500 a kg and the swiftlets that weave them are indigenous to Indonesia, Malaysia, Thailand and Vietnam. (Photo by Olivia Harris/Reuters)

Women wearing flower and sprout-like hairpins walk past an advertisement board in Beijing, China, September 25, 2015. Wearing antenna styled hairpins in the shape of various flowers and plants at scenic spots has become a new trend in Beijing. (Photo by Kim Kyung-Hoon/Reuters)

Girls of University of Cincinnati Stage Grecian Games on April 29, 1921. Garbed in costumes of ancient Greece, fair students of the University of Cincinnati, Ohio arranged a set of Grecian Games for the benefit of the University athletic fund. All of the girl students of the University, who take a great interest in outdoor games and athletics, took part in the games. The fund was greatly increased through the staging of the unique attraction and the girls purpose to give a return engagement. The accompanying photographs show the girl contestants in their Grecian costumes. Photo shows the start of the 100 yard dash. (Photo by Bettmann Archive/Getty Images)

Woman and man playing domination games in bed. (Photo by NDAB Creativity/Rex Features/Shutterstock)

A local youth, front right, scares pupils on a street as he takes part in a ceremony to exorcize evil spirits and pray for rain amid the rice planting season at Pring Ka-ek village, northwest of Phnom Penh, Cambodia, Friday, May 22, 2015. Cambodia is a country which heavily relies on agriculture as over 80 percent of its 14 million people are farmers, growing rice as their main crop. (Photo by Heng Sinith/AP Photo)

A general view shows the Krasnoyarsk hydro-electric power station on the Yenisei River near the Siberian city of Krasnoyarsk, Russia, January 13, 2016. The power plant, owned by EuroSibEnergo company, part of En+ Group, with a generating capacity of 6,000 megawatt (MW), has a ferro-concrete dam 124-metres high and 1065-metres long and is the second largest Russian hydroelectric power station. About 85% of the energy generated is intended for the Rusal Krasnoyarsk aluminium smelter, according to representatives of the power station. (Photo by Ilya Naymushin/Reuters)