A witch doctor blesses miniatures during the "Alasitas" fair, where Bolivians buy versions of goods they would like to own with the hope of acquiring them in real life during the year, in La Paz, Bolivia, January 24, 2019. REUTERS/David Mercado

Birds fly next to electricity pylons on a smoggy afternoon in the old quarters of Delhi, India, October 30, 2019. REUTERS/Adnan Abidi

Birds fly next to electricity pylons on a smoggy afternoon in the old quarters of Delhi, India, October 30, 2019. REUTERS/Adnan Abidi TPX IMAGES OF THE DAY

A man carrying a basket walks along the paddy fields early in the morning in Bhaktapur, Nepal, October 27, 2019. REUTERS/Monika Deupala

Olive trees stand in a grove in Porcuna, southern Spain October 15, 2019. Picture taken October 15, 2019. REUTERS/Marcelo del Pozo

A view of Beppu from the Beppu Bay Service Area, Japan, October 14, 2019. REUTERS/Peter Cziborra

Fog rises over a village in the mountainous district of Haraz, around 90 kilometers southwest of Sanaa, Yemen October 2, 2019. Picture taken October 2, 2019. REUTERS/Khaled Abdullah

A village is shrouded by fog in the mountainous district of Haraz, around 90 kilometers southwest of Sanaa, Yemen October 2, 2019. Picture taken October 2, 2019. REUTERS/Khaled Abdullah

Fog rises above a village in the mountainous district of Haraz, around 90 kilometers southwest of Sanaa, Yemen October 2, 2019. Picture taken October 2, 2019. REUTERS/Khaled Abdullah

A general view of the urban landscape of Tel Aviv as most Israeli Jews refrain from driving during the 25-hour period of Yom Kippur, Israel October 9, 2019. REUTERS/Ammar Awad

A morning fog is seen in the Siberian city of Omsk, Russia October 8, 2019. Picture taken October 8, 2019. REUTERS/Alexey Malgavko TPX IMAGES OF THE DAY

People are seen through a window as waves hit the coast of Sao Mateus, as Hurricane Lorenzo hits the Azores islands, in Azores, Portugal October 2, 2019. REUTERS/Rafael Marchante TPX IMAGES OF THE DAY

People are seen ahead of Pope Francis' arrival for a prayer vigil with youth at the Soamandrakizay Mess site in Antananarivo, Madagascar, September 7, 2019. REUTERS/Yara Nardi

Men walk along a street on a foggy morning in the old quarters of Delhi, India, December 31, 2018. REUTERS/Anushree Fadnavis TPX IMAGES OF THE DAY

A frosty trees are seen at the air temperature at about -28 degrees Celsius near the Siberian village of Ust-Mana outside Krasnoyarsk, Russia December 27, 2018. REUTERS/Ilya Naymushin

A man paddles a handmade boat across the Yamuna river on a foggy winter morning in New Delhi, India December 27, 2018. REUTERS/Adnan Abidi TPX IMAGES OF THE DAY

Men paddle their handmade boats across the Yamuna river on a foggy winter morning in New Delhi, India December 27, 2018. REUTERS/Adnan Abidi

A man paddles a handmade boat across the Yamuna river on a foggy winter morning in New Delhi, India December 27, 2018. REUTERS/Adnan Abidi

Windows take on different shapes as they reflect upon the water along a wharf in Portland, Maine, U.S., December 24, 2018. REUTERS/Kevin Lamarque TPX IMAGES OF THE DAY

Thousands of starlings fly in a 'murmuration' as they return to roost at dusk near Ely in Cambridgeshire, Britain December 24, 2018. REUTERS/Hannah McKay TPX IMAGES OF THE DAY

A man feeds seagulls as he stands on the banks of Yamuna river on a foggy winter morning in New Delhi, India, December 24, 2018. REUTERS/Adnan Abidi TPX IMAGES OF THE DAY

The sunset is seen during a poor air quality day in Bangkok, Thailand, December 21, 2018. REUTERS/Jorge Silva TPX IMAGES OF THE DAY

The moon rises during a poor air quality day in Bangkok, Thailand, December 21, 2018. REUTERS/Jorge Silva

The sunset is seen during a poor air quality day in Bangkok, Thailand, December 21, 2018. REUTERS/Jorge Silva

The sunset is seen during a poor air quality day in Bangkok, Thailand, December 21, 2018. REUTERS/Jorge Silva

A man walks through a vegetable field on a foggy winter morning in New Delhi, India, December 18, 2018. REUTERS/Anushree Fadnavis TPX IMAGES OF THE DAY

A man walks through a vegetable field on a foggy winter morning in New Delhi, India, December 18, 2018. REUTERS/Anushree Fadnavis

Smog is seen near transmission towers in Bedzin, near Katowice, Poland, December 5, 2018. REUTERS/Kacper Pempel

Smog is seen in this general view of the Upper Silesian Industrial Region from Bedzin, near Katowice, Poland, December 5, 2018. REUTERS/Kacper Pempel

Smog is seen during sunset in this general view of the Upper Silesian Industrial Region from Bedzin, near Katowice, Poland, December 5, 2018. REUTERS/Kacper Pempel

Smog is seen during sunset in this general view of the Upper Silesian Industrial Region from Bedzin, near Katowice, Poland, December 5, 2018. REUTERS/Kacper Pempel

Smog is seen in this general view of the Upper Silesian Industrial Region from Bedzin, near Katowice, Poland, December 5, 2018. REUTERS/Kacper Pempel

General view of the city as smog blankets Sarajevo, Bosnia and Herzegovina December 3, 2018. Picture is taken December 3, 2018. REUTERS/Dado Ruvic

General view of the city as smog blankets Sarajevo, Bosnia and Herzegovina December 3, 2018. Picture is taken December 3, 2018. REUTERS/Dado Ruvic

General view of the city as smog blankets Sarajevo, Bosnia and Herzegovina December 3, 2018. Picture is taken December 3,2018. REUTERS/Dado Ruvic

General view of the city as smog blankets Sarajevo, Bosnia and Herzegovina December 3, 2018. Picture is taken December 3, 2018. REUTERS/Dado Ruvic

General view of the city as smog blankets Sarajevo, Bosnia and Herzegovina December 3, 2018. Picture is taken December 3, 2018. REUTERS/Dado Ruvic

General view of the city as smog blankets Sarajevo, Bosnia and Herzegovina December 3, 2018. Picture is taken December 3, 2018. REUTERS/Dado Ruvic

General view of the city as smog blankets Sarajevo, Bosnia and Herzegovina December 3, 2018. Picture is taken December 3, 2018. REUTERS/Dado Ruvic

General view of the city as smog blankets Sarajevo, Bosnia and Herzegovina December 3, 2018. Picture is taken December 3, 2018. REUTERS/Dado Ruvic

People walk on a pedestrian bridge as heavy smog blankets China's capital after the city issued its first air pollution alert for the winter season, in Beijing, China November 26, 2018. REUTERS/Jason Lee TPX IMAGES OF THE DAY

People walk on a pedestrian bridge as heavy smog blankets China's capital after the city issued its first air pollution alert for the winter season, in Beijing, China November 26, 2018. REUTERS/Jason Lee

Protesters wearing yellow vests, a symbol of a French drivers' protest against higher fuel prices, are seen during riots on the Champs-Elysees in Paris, France, November 24, 2018. REUTERS/Gonzalo Fuentes

Clouds can be seen above a dust storm as it descends upon the city of Sydney in Australia, November 22, 2018. Picture taken through the window. REUTERS/David Gray

Snow covered trees are seen on a foggy day in the Buda hills in Budapest, Hungary, November 19, 2018. REUTERS/Bernadett Szabo

People walk on a foggy day in the Buda hills in Budapest, Hungary, November 19, 2018. REUTERS/Bernadett Szabo

Snow covered trees are seen on a foggy day in the Buda hills in Budapest, Hungary, November 19, 2018. REUTERS/Bernadett Szabo

Snow covered trees are seen on a foggy day in the Buda hills in Budapest, Hungary, November 19, 2018. REUTERS/Bernadett Szabo

Snow covered trees are seen on a foggy day in the Buda hills in Budapest, Hungary, November 19, 2018. REUTERS/Bernadett Szabo

Heavy fog covers the city of Minsk, Belarus November 9, 2018. REUTERS/Vasily Fedosenko TPX IMAGES OF THE DAY

Heavy fog covers the city of Minsk, Belarus November 9, 2018. REUTERS/Vasily Fedosenko

Heavy fog covers the city of Minsk, Belarus November 9, 2018. REUTERS/Vasily Fedosenko

Heavy fog covers the city of Minsk, Belarus November 9, 2018. REUTERS/Vasily Fedosenko

Heavy fog covers the city of Minsk, Belarus November 9, 2018. REUTERS/Vasily Fedosenko

Sunlight reflects from windows of an apartment building on a foggy autumn day in Kiev, Ukraine November 8, 2018. REUTERS/Valentyn Ogirenko TPX IMAGES OF THE DAY

Sunlight reflects from windows of an apartment building on a foggy autumn day in Kiev, Ukraine November 8, 2018. REUTERS/Valentyn Ogirenko TPX IMAGES OF THE DAY

Sunlight reflects from windows of an apartment building on a foggy autumn day in Kiev, Ukraine November 8, 2018. REUTERS/Valentyn Ogirenko TPX IMAGES OF THE DAY

A bird flies in a front of an orthodox church on a foggy autumn day in Kiev, Ukraine November 8, 2018. REUTERS/Valentyn Ogirenko

Sunlight reflects from windows of an apartment building on a foggy autumn day in Kiev, Ukraine November 8, 2018. REUTERS/Valentyn Ogirenko

A man with his face covered walks in front of the India Gate amidst smog in the early morning in New Delhi, India, November 8, 2018. REUTERS/Anushree Fadnavis TPX IMAGES OF THE DAY