fog

A man rides an escalator in front of hig...A man rides an escalator in front of high rise buildings in the financial district Lujiazui in Shanghai on April 6, 2016.  / AFP PHOTO / JOHANNES EISELEJOHANNES EISELE/AFP/Getty Images

Johannes Eiseke/AFP

A man rides an escalator in front of high rise buildings in the financial district Lujiazui in Shanghai  

Still thousands of refugees massing in Idomeni to enter Macedonia...epa05205764 Refugees try to warm themselves with a fire at a refugee camp during a foggy day at the border between Greece and the Former Yugoslav Republic of Macedonia (FYROM), near Idomeni, northern Greece, 11 March 2016. Greece has registered in its territory some 36,000 migrants trapped due to entry restrictions already imposed by Macedonia in recent months, by denying entry to all those who are considered economic migrants, prohibiting the passage of Afghans, and finally denying entry to all Syrians and Iraqis who are not from combat areas.  EPA/YANNIS KOLESIDIS

Yannis Kolesidis/EPA

Refugees try to warm themselves with a fire at a refugee camp during a foggy day at the border between Greece and the Former Yugoslav Republic of Macedonia near Idomeni, Greece 

Fog Hovers Beneath Christ the Redeemer Statue...RIO DE JANEIRO, BRAZIL - JANUARY 04:  Fog hovers beneath Christ the Redeemer statue with the Cantagalo 'favela' in the foreground on January 4, 2016 in Rio de Janeiro, Brazil. The Rio 2016 Olympic Games commence in August.  (Photo by Mario Tama/Getty Images)

Mario Tama/Getty

Fog hovers beneath Christ the Redeemer statue with the Cantagalo ‘favela’ in the foreground on Monday in Rio de Janeiro, Brazil

An elevation in the city of Sarajevo, Bosnia and Herzegovina, covered in a thick layer of fog, on Monday. Due to high levels of NO2 (nitrogen dioxide) in the air over the city and a certain meteorological condition, residents of Sarajevo were recommended to reduce their movement in the streets and to reduce car traffic

Fehim Demir/EPA

An elevation in the city of Sarajevo, Bosnia and Herzegovina, covered in a thick layer of fog, on Monday. Due to high levels of NO2 (nitrogen dioxide) in the air over the city and a certain meteorological condition, residents of Sarajevo were recommended to reduce their movement in the streets and to reduce car traffic

Journalists hover in a cage over fog covered Frankfurt am Main to watch the construction site of the Henninger tower in Frankfurt am Main, central Germany, on Tuesday

Arne Dedert/DPA/AFP

Journalists hover in a cage over fog covered Frankfurt am Main to watch the construction site of the Henninger tower in Frankfurt am Main, central Germany, on Tuesday

A combo shows a morning commuter walking in front of the China Central Television (CCTV) building on a smoggy day and a sunny day

Damir Sagolj/Reuters

A combination photo shows a morning commuter walking in front of the China Central Television (CCTV) building on a smoggy day on December 1, 2015 (top), and on a sunny day on December 2, 2015 (bottom), after a fresh cold front cleared the smog that was blanketing Beijing, China.

India Kashmir Weather

Mukhtar Khan/AP

A Kashmiri man walks during a foggy morning in Srinagar, Indian controlled Kashmir, on Wednesday. Foggy weather in Kashmir valley affected surface and air traffic causing flight cancellations to and from Srinagar International Airport, stranding hundreds of passengers.

Workers walk past a billboard display showing a scene of Central Business District, as capital city skylines are shrouded with pollutant haze in Beijing, China, Monday, Nov. 9, 2015. Heading into this month's Paris meeting, the world's biggest source of climate-changing gases has yet to accept binding limits. But it has invested in solar, wind and hydro power to clean up its smog-choked cities and curb surging demand for imported oil and gas. That contributed last year to a surprise fall in coal consumption. (AP Photo/Andy Wong)

Andy Wong/AP

Workers walk past a billboard display showing a scene of Central Business District, as capital city skylines are shrouded with pollutant haze in Beijing, China

A tree stands in the morning fog in Dresden, Germany

  © Burgi/EPA

A tree stands in the morning fog in Dresden, Germany

A cyclist drives past wafts of mist rising from a tributary of the Weisse Elster river in Leipzig, eastern Germany, on Tuesday

Hendrik Schmidt/AFP

A cyclist drives past wafts of mist rising from a tributary of the Weisse Elster river in Leipzig, eastern Germany, on Tuesday

A seagull flies past Westminster Bridge during a foggy day in central London, November 2, 2015. Airports across Britain suffered disruption on Monday as heavy fog led to delays and cancellations for a second day. Flights to and from London airports were being affected, while foggy conditions in the capital and across Europe were causing problems to airports around the country.REUTERS/Stefan Wermuth

Stefan Wermuth/Reuters

A seagull flies past Westminster Bridge during a foggy day in central London today. Airports across Britain suffered disruption on Monday as heavy fog led to delays and cancellations for a second day. Flights to and from London airports were being affected, while foggy conditions in the capital and across Europe were causing problems to airports around the country. 

Motorists ride on a road as thick haze from forest fires shroud the city in Palangkaraya, Central Borneo, Indonesia, Tuesday, Oct. 27, 2015. The haze has blanketed parts of western Indonesia for about two months and affected neighboring countries like Singapore, Malaysia and Thailand

AP

Motorists ride on a road as thick haze from forest fires shroud the city in Palangkaraya, Central Borneo, Indonesia, Tuesday. The haze has blanketed parts of western Indonesia for about two months and affected neighboring countries like Singapore, Malaysia and Thailand

Chinese tourists walk across a glass-bottomed suspension bridge in the Shinuizhai mountains in Pingjang county, Hunan province some 150 kilometers from Changsha. The bridge, originally a wooden walkway spanning some 300 meters across the 180-meter deep valley, reopened two weeks ago following renovations as a glass-bottomed tourist attraction

Johannes Eisele/AFP

Chinese tourists walk across a glass-bottomed suspension bridge in the Shinuizhai mountains in Pingjang county, Hunan province some 150 kilometers from Changsha

A general view shows the part of the skyline of Dubai covered in an early morning fog on October 5, 2015

Rene Slama/AFP

A general view shows the part of the skyline of Dubai covered in an early morning fog on Monday

Residential buildings are seen among fog in Qingdao...Residential buildings are seen among fog in Qingdao, Shandong province, March 27, 2015. China's property sales in the first two months of 2015 dropped by the most in three years amid a glut of housing supply, and real estate investment growth eased. REUTERS/Stringer TPX IMAGES OF THE DAY CHINA OUT. NO COMMERCIAL OR EDITORIAL SALES IN CHINA

Reuters

Fog covers residential buildings in Qingdao, China. China’s property sales in the first two months of 2015 dropped by the most in three years 

People do morning exercises on a polluted day in Jiaozuo, Henan province, March 16, 2015. China cannot relent on efforts to tackle pollution, though a rapid turnaround should not be expected, the environment minister told a news conference early this month during China's annual parliamentary meeting.

China Daily/Reuters

People perform morning exercises on a polluted day in Jiaozuo, Henan province, China on Monday.

Indian students travel on a horse cart surrounded by fog in Jammu, India, Thursday, Dec.18, 2014. As winter sets in, thick fog engulfs most of north India early mornings.

Channi Anand/AP

Students travel via horse and cart surrounded by fog in Jammu, India. As winter sets in, thick fog engulfs most of north India early mornings

Men play cricket in a public park on a foggy morning in Kolkata

Rupak De Chowdhuri/Reuters

Men play cricket in a public park on a foggy morning in Kolkata, India on Friday

Kashmiris walk towards a polling station to cast their votes on a cold and foggy morning in Kulangham, some 68 kilometers north of Srinagar, India on Tuesday. The second phase of the five-phased state elections is being held Tuesday.

Dar Yasin/AP

Kashmiris walk towards a polling station to cast their votes on a cold and foggy morning in Kulangham, some 68km north of Srinagar, India, on Tuesday.

An Indian jockey leads his horse off the track after attending a practice session

Dibyangshu Sarkar/AFP/Getty Images

An Indian jockey leads his horse off the track after attending a practice session at The Royal Calcutta Turf Club on a foggy morning in Kolkata on Friday