Somali men carry swordfish from the sea to a market in the capital Mogadishu, Somalia Thursday, April 23, 2015. (Photo by Farah Abdi Warsameh/AP Photo)

The Acura Stage area is flooded after a storm dumped several inches of rain on the second Saturday of the New Orleans Jazz Fest at the Fair Grounds, Saturday, April 30, 2016. (Photo by David Grunfeld/NOLA.com/The Times-Picayune via AP Photo)

An Egyptian carries bread tray over his bicycle, in Cairo, Egypt, Saturday, November 19, 2016. Egypt is currently suffering an acute foreign currency shortage because of the decimation of its lucrative tourism industry, double digit rates of inflation and unemployment. (Photo by Amr Nabil/AP Photo)

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 man and a girl take a dip in icy waters during celebrations for the Orthodox Epiphany in the Sea of Japan in the far eastern city of Vladivostok, Russia, January 19, 2016. Orthodox believers mark Epiphany on January 19 by immersing themselves in icy waters regardless of the weather. (Photo by Yuri Maltsev/Reuters)

The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)

In this photo taken Saturday, February 14, 2015, Benjamin Miller, 20, from Georgia, in the US, is gored by a bull during the “Carnaval del Toro” in Ciudad Rodrigo, Spain. An American youth is recovering in the intensive-care unit of a hospital in western Salamanca after being savagely gored during a bullfighting festival celebrating Carnival, officials said Sunday. Surgeon Enrique Crespo said he was called to operate on 20-year-old Benjamin Miller from Georgia, who had been gored and tossed by a large fighting bull on Saturday, the first day of nearby Ciudad Rodrigo's “Carnaval del Toro”. (Photo by Jose Vicente/AP Photo)

A Felix Airways plane is seen after it was destroyed by an airstrike at the international airport of Yemen's capital Sanaa, April 29, 2015. Jets from a Saudi-led alliance destroyed the runway of Yemen's Sanaa airport on Tuesday to prevent an Iranian plane from landing there, Saudi Arabia said, as fighting across the country killed at least 30 people. Airport officials said the strikes set a civilian aircraft operated by Yemeni Felix Airways ablaze. (Photo by Khaled Abdullah/Reuters)