A Chinese man wears a mask to protect against pollution as he waits at a red light while commuting to work in heavy smog on December 8, 2015 in Beijing, China. The Beijing government issued a 'red alert' for the first time since new standards were introduced earlier this year as the city and many parts of northern China were shrouded in heavy pollution. Levels of PM 2.5, considered the most hazardous, crossed 400 units in Beijing, lower than last week, but still nearly 20 times the acceptable standard set by the World Health Organization. The governments of more than 190 countries are meeting in Paris to set targets on reducing carbon emissions in an attempt to forge a new global agreement on climate change. (Photo by Kevin Frayer/Getty Images)

A man holds an idol of Hindu God Ganesha before immersing it in the Bay of Bengal during Ganesh Chaturthi festival in Chennai, India, Sunday, September 20, 2015. The festival marks the birth of Ganesha who is widely worshiped by Hindus as the god of wisdom, prosperity and good fortune. (Photo by Arun Sankar K./AP Photo)

A working team appointed by the Archaeological Superintendence of Pompeii performs a Cat scan (Computerized axial tomography) one out of thirty casts of victims of the eruption of Vesuvius in 79 AD in Pompeii, in Napoli, Italy, 29 September 2015. The project which aims to trace the habits of life, employment and social class of the victims, involves a working team of archeologists, anthropologists, radiologists, dentists and engineers to obtain results from the scan. (Photo by Cesare Abbate/EPA)

Korean Air flight attendants photograph a therapy dog dressed in a Superman Halloween costume, as part of a program to de-stress passengers at the international boarding gate area of LAX airport in Los Angeles, California, United States, October 27, 2015. (Photo by Lucy Nicholson/Reuters)

Girls enjoy nice weather at a park in front of the Pothonggang Department Store in central Pyongyang October 11, 2015. (Photo by Damir Sagolj/Reuters)

A young arab boy, armed with a rifle and a knife, in the Aden Protectorate near Yemen. (Photo by Richards/Fox Photos/Getty Images). February 1938

Model Amanda Kaspor of Highland, Michigan poses with the CT&T e-Zone Plus electric car is displayed during the press preview for the world automotive media North American International Auto Show at the Cobo Center January 12, 2010 in Detroit, Michigan. (Photo by Bryan Mitchell/Getty Images)

A beachgoer walks past a buoy that washed ashore after Hurricane Isabel made landfall September 19, 2003 in Virginia Beach, Virginia. (Photo by Joe Raedle/Getty Images)