Smoke from the Caldor Fire shrouds vegetation near the town of Pollock Pines, California, U.S. August 18, 2021. REUTERS/Fred Greaves

Smoke from the Caldor Fire shrouds vegetation near the town of Pollock Pines, California, U.S. August 18, 2021. REUTERS/Fred Greaves

Smoke from the Caldor Fire shrouds vegetation near the town of Pollock Pines, California, U.S. August 18, 2021. REUTERS/Fred Greaves

Houses are seen shrouded in smoke as a wildfire burns outside the village of Taastaakh in the region of Yakutia, Russia August 11, 2021. Picture taken August 11, 2021. REUTERS/Alexander Reshetnikov

The Pioneer Cafe on the Main Street is seen shrouded in smoke, as the Dixie Fire approaches Greenville, California, U.S., July 26, 2021. Picture taken July 26, 2021. REUTERS/David Swanson

The Pioneer Cafe on the Main Street is seen shrouded in smoke, as the Dixie Fire approaches Greenville, California, U.S., July 26, 2021. Picture taken July 26, 2021. REUTERS/David Swanson

A ferry passes under the Sydney Harbour Bridge, seen shrouded in morning fog, during a lockdown to curb the spread of a coronavirus disease (COVID-19) outbreak in Sydney, Australia, July 1, 2021. REUTERS/Loren Elliott

A man wearing a protective face mask takes in the waterfront view under the Sydney Harbour Bridge, seen shrouded in morning fog, during a lockdown to curb the spread of a coronavirus disease (COVID-19) outbreak in Sydney, Australia, July 1, 2021. REUTERS/Loren Elliott

A man wearing a protective face mask walks past the Sydney Opera House, seen shrouded in fog, during a lockdown to curb the spread of a coronavirus disease (COVID-19) outbreak in Sydney, Australia, July 1, 2021. REUTERS/Loren Elliott TPX IMAGES OF THE DAY

Fog shrouds high-rise buildings in the city centre as numerous industries face the economic ramifications of a lockdown to curb the spread of a coronavirus disease (COVID-19) outbreak in Sydney, Australia, July 1, 2021. REUTERS/Loren Elliott

A woman jogs along the waterfront past the Sydney Harbour Bridge, seen shrouded in fog, during a lockdown to curb the spread of a coronavirus disease (COVID-19) outbreak in Sydney, Australia, June 30, 2021. REUTERS/Loren Elliott

A man wearing a protective face mask takes in the waterfront view underneath the Sydney Harbour Bridge, seen shrouded in fog, during a lockdown to curb the spread of a coronavirus disease (COVID-19) outbreak in Sydney, Australia, June 30, 2021. REUTERS/Loren Elliott TPX IMAGES OF THE DAY

A man takes in the waterfront view underneath the Sydney Harbour Bridge, seen shrouded in fog, during a lockdown to curb the spread of a coronavirus disease (COVID-19) outbreak in Sydney, Australia, June 30, 2021. REUTERS/Loren Elliott

A fisherman leaves his spot underneath the Sydney Harbour Bridge, seen shrouded in fog, during a lockdown to curb the spread of a coronavirus disease (COVID-19) outbreak in Sydney, Australia, June 30, 2021. REUTERS/Loren Elliott

A cyclist rides past trees shrouded in fog on Table Mountain in Cape Town, South Africa, June 12, 2021. REUTERS/Mike Hutchings

Smoke shrouds trees as a bushfire burns on the slopes of Table Mountain in Cape Town, South Africa, April 20, 2021. REUTERS/Mike Hutchings

Smoke shrouds trees as a bushfire burns on the slopes of Table Mountain in Cape Town, South Africa, April 20, 2021. REUTERS/Mike Hutchings

Smoke shrouded trees are seen, as a bushfire burns on the slopes of Table Mountain in Cape Town, South Africa, April 20, 2021. REUTERS/Mike Hutchings

Smoke shrouded trees are seen, as a bushfire burns on the slopes of Table Mountain in Cape Town, South Africa, April 20, 2021. REUTERS/Mike Hutchings TPX IMAGES OF THE DAY

A house is seen shrouded in smoke as firefighters battle to contain a fire fanned by strong winds on the slopes of Table Mountain in Cape Town, South Africa, April 19, 2021. REUTERS/Mike Hutchings

A high speed train travels past buildings shrouded in sand and dust amid a duststorm in Beijing, China April 15, 2021. Picture taken through a window. REUTERS/Tingshu Wang

Buildings in the Central Business District (CBD) are seen shrouded in sand and dust amid a duststorm in Beijing, China April 15, 2021. Picture taken through a window. REUTERS/Tingshu Wang

Buildings in the Central Business District (CBD) are seen shrouded in sand and dust amid a duststorm in Beijing, China April 15, 2021. Picture taken through a window. REUTERS/Tingshu Wang

A sanitation worker rides a vehicle past Central Business District (CBD) buildings shrouded in sand and dust amid a duststorm in Beijing, China April 15, 2021. REUTERS/Tingshu Wang

A person walks as darkness shrouds the north of the island after La Soufriere volcano erupted on the eastern Caribbean island of St. Vincent April 9, 2021. REUTERS/Robertson S. Henry

Darkness shrouds the north of the island as La Soufriere volcano erupts on the eastern Caribbean island of St. Vincent April 9, 2021. REUTERS/Robertson S. Henry

Mohamed Mahmoud, 65 years old, a traditional undertaker, looks on at his shop next to white shrouds and fragrant water with other accessories carried by his son in the Shobra district of Cairo, Egypt April 7, 2021. Picture taken April 7, 2021. REUTERS/Amr Abdallah Dalsh

A staff member stands near a Boeing 737-800 airplane of Air China on the tarmac of Beijing Capital International Airport, which is shrouded in dust as the city is hit by a sandstorm, in Beijing, China March 28, 2021. REUTERS/Carlos Garcia Rawlins

Staff members stand near a Boeing 737-800 airplane of Air China on the tarmac of Beijing Capital International Airport, which is shrouded in dust as the city is hit by a sandstorm, in Beijing, China March 28, 2021. REUTERS/Carlos Garcia Rawlins

Construction workers are seen in front of the CCTV headquarters shrouded in dust as the city is hit by a sandstorm, in Beijing, China March 28, 2021. REUTERS/Martin Pollard

A general view of the city shrouded in smog after a sandstorm, in central Beijing, China March 15, 2021. REUTERS/Tingshu Wang

A general view of the city shrouded in smog after a sandstorm, in central Beijing, China March 15, 2021. REUTERS/Tingshu Wang

A general view of the city shrouded in smog after a sandstorm, in central Beijing, China March 15, 2021. REUTERS/Tingshu Wang

A road worker uses his smartphone in Beijing, China, as the city is shrouded in haze after a sandstorm, March 15, 2021. REUTERS/Thomas Peter

Road workers go about their day in Beijing, China, as the city is shrouded in haze after a sandstorm, March 15, 2021. REUTERS/Thomas Peter

A woman crosses a road with a head covering in Beijing, China, as the city is shrouded in haze after a sandstorm, March 15, 2021. REUTERS/Thomas Peter

People walk in the Central Business District of Beijing, China, as the city skyline is shrouded in haze after a sandstorm, March 15, 2021. REUTERS/Thomas Peter

A man walks past buildings shrouded in haze after a sandstorm in the Central Business District of Beijing, China March 15, 2021. REUTERS/Thomas Peter

A woman wearing a head covering is seen in front of the headquarters of China's state media broadcaster CCTV that is shrouded in haze after a sandstorm in the Central Business District of Beijing, China March 15, 2021. REUTERS/Thomas Peter

A paramilitary police officer stands guard on Tiananmen Square shrouded in smog, before the closing session of the Chinese People's Political Consultative Conference (CPPCC) at the Great Hall of the People on a polluted day in Beijing, China March 10, 2021. REUTERS/Carlos Garcia Rawlins

A man holds his mobile phone on Tiananmen Square shrouded in smog, before the closing session of the Chinese People's Political Consultative Conference (CPPCC) at the Great Hall of the People on a polluted day in Beijing, China March 10, 2021. REUTERS/Carlos Garcia Rawlins

A student stands on a sports field shrouded in smog on a polluted day in Beijing, China March 10, 2021. REUTERS/Carlos Garcia Rawlins

Fishermen are pictured on their pirogue as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

A street vendor walks past the Massalikoul Djinane mosque as dust carried by winds from the Sahara desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

Fishermen are pictured on their pirogue as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

Fishermen are pictured on their pirogue as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

People are pictured at the fishing port of Soumbedioune as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

Men talk as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

A boy jumps over pirogues as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

Fishermen are pictured on their pirogue as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

Fishermen are pictured on their pirogue as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

Men are pictured at the fishing port of Soumbedioune as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra

Fishermen are pictured on their pirogue as dust carried by winds from the Sahara Desert shrouds Dakar, Senegal February 18, 2021. REUTERS/Zohra Bensemra TPX IMAGES OF THE DAY

The Washington Monument is shrouded in smoke after fireworks during the "Celebrating America" event following the inauguration of Joe Biden as the 46th President of the United States, in Washington, U.S., January 20, 2021. REUTERS/Tom Brenner

Buildings are shrouded in haze in Bangkok, Thailand December 15, 2020. REUTERS/Athit Perawongmetha

Buildings are shrouded in haze in Bangkok, Thailand December 15, 2020. REUTERS/Athit Perawongmetha

Buildings are shrouded in haze in Bangkok, Thailand December 15, 2020. REUTERS/Athit Perawongmetha

Buildings are shrouded in haze in Bangkok, Thailand December 15, 2020. REUTERS/Athit Perawongmetha

Buildings are seen shrouded in haze in Bangkok, Thailand December 15, 2020. REUTERS/Soe Zeya Tun