Heavy fog rolls by early in the morning near the Dubai Marina, United Arab Emirates, on Nov. 21, 2007. (Steve Crisp/Reuters)

A bird flies in front of city sky scrapers covered by fog in the center of Warsaw, Poland, on Feb. 23. (Kacper Pempel/Reuters)

Buildings are seen among fog in Qingdao, Shandong province, China, on March 27. (Reuters)

Low level clouds float over Dubai's Marina area as the sun sets on Dubai, United Arab Emirates on New Year's Eve, 2008. (Steve Crisp/Reuters)

Early morning fog enshrouds Cape Town's Green Point 2010 FIFA Soccer World Cup Stadium on Aug. 25, 2009. (Mike Hutchings/Reuters)

People walk on a pier in the Hudson River as clouds shroud One World Trade Center (center) and the skyline of Lower Manhattan in New York, as seen from Hoboken, New Jersey, on May 25, 2012. (Gary Hershorn/Reuters)

Residential buildings are seen among fog in Qingdao, Shandong province, China on March 27. (Reuters)

A cruise ship makes its way past New York's Lower Manhattan and One World Trade Center as steam rises from the Hudson River as seen from Hoboken, New Jersey, on Jan. 11, 2014. (Gary Hershorn/Reuters)

Buildings are seen amid heavy fog in Wuhan, Hubei province, China, on Dec. 3, 2009. (Reuters)

The skyline of San Francisco appears above the evening fog as the suns sets on the Marin Headlands in Sausalito, Calif., on April 18, 2009. (Robert Galbraith.Reuters)

Skyscrapers Shanghai World Financial Center (right) and Jin Mao Tower are seen during heavy rain at the financial district of Pudong in Shanghai, China, on May 15, 2015. (Aly Song/Reuters)

A long exposure picture shows a seasonal fog illuminated by the lights of Cape Town harbor as the city prepares for the start of the southern hemisphere winter in South Africa, on May 8, 2012. (Mike Hutchings/Reuters)