A protester clashes with a police officer in Athens' central Syntagma (Constitution) Square in this June 15, 2011 file photo. Greece triggered the regional financial crisis in 2009 when a far higher budget deficit than previously calculated emerged. The collapse of talks with creditors in Paris last November set off a month-long sequence of events leading to elections this week and proving Greece is still the region's weak link. The vote is expected to be won by Syriza, a far-left party opposed to the bailout, worrying investors and creditors alike. (Photo by Yannis Behrakis/Reuters)

An aircraft passes over houses at it lands at Heathrow Airport near London, Britain, December 11, 2015. Picture taken December 11, 2015. (Photo by Neil Hall/Reuters)

People walk during a polluted day in Shenyang, Liaoning province, March 31, 2016. (Photo by Reuters/Stringer)

Laura Giombini of Italy reacts during the Women's Beach Volleyball preliminary round Pool D match against Jamie Lynn Broder and Kristina Valjas of Canada on Day 2 of the Rio 2016 Olympic Games at the Beach Volleyball Arena on August 7, 2016 in Rio de Janeiro, Brazil. (Photo by Shaun Botterill/Getty Images)

A fishmonger carries a shark on his motorcycle in Padang, West Sumatra, Indonesia August 25, 2016. (Photo by Iggoy el Fitra/Reuters/Antara Foto)

A flood-affected couple sits along a flooded roadside under a picture of Jayalalithaa Jayaram, chief minister of the southern Indian state of Tamil Nadu, in Chennai, India, December 6, 2015. (Photo by Anindito Mukherjee/Reuters)

Trees in a park are illuminated with a red light as a part of an art project in Timmendorfer Strand, northern Germany Wednesday, October 26, 2016. (Photo by Michael Probst/AP Photo)

Models clad in costumes of video game charactors pose at a game booth during the Tokyo Game Show 2016 in Chiba, suburb of Tokyo, on September 15, 2016. Sony took centre stage at the annual four-day event, with its virtual reality headset ready to hit store shelves for the Christmas shopping season. (Photo by Toru Yamanaka/AFP Photo)