A man shows a graphic delivered from a prototype device which measures the coronavirus disease (COVID-19) contagion risk levels by monitoring CO2 emissions in real time inside enclosed spaces, in Santiago, Chile June 22, 2021. Picture taken June 22, 2021. REUTERS/Ivan Alvarado

Ricardo Finger, Ph.D. Electrical Engineering, shows a prototype device to measure the coronavirus disease (COVID-19) contagion risk levels by monitoring CO2 emissions in real time inside enclosed spaces, in Santiago, Chile June 22, 2021. Picture taken June 22, 2021. REUTERS/Ivan Alvarado

Ricardo Finger, Ph.D. Electrical Engineering, shows a prototype device to measure the coronavirus disease (COVID-19) contagion risk levels by monitoring CO2 emissions in real time inside enclosed spaces, in Santiago, Chile June 22, 2021. Picture taken June 22, 2021. REUTERS/Ivan Alvarado

Ricardo Finger, Ph.D. Electrical Engineering, checks a prototype device to measure the coronavirus disease (COVID-19) contagion risk levels by monitoring CO2 emissions in real time inside enclosed spaces, in Santiago, Chile June 22, 2021. Picture taken June 22, 2021. REUTERS/Ivan Alvarado

A view of a prototype device to measure the coronavirus disease (COVID-19) contagion risk levels by monitoring CO2 emissions in real time inside enclosed spaces, in Santiago, Chile June 22, 2021. Picture taken June 22, 2021. REUTERS/Ivan Alvarado

Belgium's Health and Deputy Prime Minister Frank Vandenbroucke speaks next to Prime Minister Alexander De Croo at a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Belgium's Health and Deputy Prime Minister Frank Vandenbroucke speaks next to Prime Minister Alexander De Croo at a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Frank Vandenbroucke, health and deputy prime minister, speaks at a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Frank Vandenbroucke, health and deputy prime minister, speaks at a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

German Community Minister President Oliver Paasch speaks at a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Walloon Minister President Elio Di Rupo attends a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Belgium's Prime Minister Alexander De Croo attends a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Brussels Minister President Pierre-Yves Jeholet attends a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Belgium's Prime Minister Alexander De Croo attends a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Belgium's Prime Minister Alexander De Croo attends a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Flemish Minister President Jan Jambon gives a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Flemish Minister President Jan Jambon gives a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Flemish Minister President Jan Jambon gives a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Brussels region Minister-President Rudi Vervoort gives a news conference after a government meeting to announce the new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Brussels region Minister-President Rudi Vervoort gives a news conference after a government meeting to announce the new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Walloon Minister President Elio Di Rupo, Belgium's Prime Minister Alexander De Croo and Flemish Minister President Jan Jambon attend a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Belgium's Prime Minister Alexander De Croo and Flemish Minister President Jan Jambon attend a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Walloon Minister President Elio Di Rupo, Belgium's Prime Minister Alexander De Croo and Flemish Minister President Jan Jambon attend a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Walloon Minister President Elio Di Rupo, Belgium's Prime Minister Alexander De Croo and Flemish Minister President Jan Jambon attend a news conference after a government meeting to announce new coronavirus-related measures in Brussels, Belgium June 18, 2021. Bert Van Den Broucke/Pool via REUTERS

Passengers of the cruise ship 'Mein Schiff 2' of TUI Cruises stand at Bellver park in Palma de Mallorca, after disembarking to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

Passengers of the cruise ship 'Mein Schiff 2' of TUI Cruises stand at Bellver park in Palma de Mallorca, after disembarking to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

The cruise ship 'Mein Schiff 2' of TUI Cruises is docked in Palma de Mallorca port where passengers will disembark to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

Passengers of the cruise ship 'Mein Schiff 2' of TUI Cruises stand at Bellver park in Palma de Mallorca, after disembarking to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

Passengers of the cruise ship 'Mein Schiff 2' of TUI Cruises stand at Bellver park in Palma de Mallorca, after disembarking to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

Passengers of the cruise ship 'Mein Schiff 2' of TUI Cruises stand at Bellver park in Palma de Mallorca, after disembarking to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

The cruise ship 'Mein Schiff 2' of TUI Cruises is docked in Palma de Mallorca port where passengers will disembark to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

The cruise ship 'Mein Schiff 2' of TUI Cruises is docked in Palma de Mallorca port where passengers will disembark to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

The cruise ship 'Mein Schiff 2' of TUI Cruises is docked in Palma de Mallorca port where passengers will disembark to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

The cruise ship 'Mein Schiff 2' of TUI Cruises is docked in Palma de Mallorca port where passengers will disembark to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

The cruise ship 'Mein Schiff 2' of TUI Cruises is docked in Palma de Mallorca port where passengers will disembark to tour the city in bubble groups as a measure against the coronavirus disease (COVID-19) in Mallorca, Spain, June 17, 2021. REUTERS/Enrique Calvo

Michael Martin measures the water drop in his garden well in the village of Vaclavice near the town of Hradek nad Nisou, Czech Republic, June 15, 2021. Picture taken June 15, 2021. REUTERS/David W Cerny

Michael Martin measures the water drop in his garden well in the village of Vaclavice near the town of Hradek nad Nisou, Czech Republic, June 15, 2021. Picture taken June 15, 2021. REUTERS/David W Cerny

ATTENTION EDITORS - EMBARGOED TO 0401 GMT JUNE 11, 2021 Robots measure preprogrammed surface and alignment points of the frame to a 2021 Jeep Grand Cherokee L on the assembly line at the Detroit Assembly Complex - Mack Plant in Detroit, Michigan, U.S., June 10, 2021. Picture taken June 10, 2021. REUTERS/Rebecca Cook

German Chancellor Angela Merkel wears her protective mask after a news conference following a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

German government spokesman Steffen Seibert attends a news conference following a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

German Chancellor Angela Merkel addresses a news conference after a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

German Chancellor Angela Merkel takes her documents after a news conference following a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

German Chancellor Angela Merkel uses her mobile phone during a news conference after a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

German Chancellor Angela Merkel addresses a news conference after a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

German Chancellor Angela Merkel addresses a news conference after a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

Bavarian state prime minister Markus Soeder is seen on a video screen during a news conference of German Chancellor Angela Merkel after a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

Bavarian state prime minister Markus Soeder is seen on a video screen during a news conference of German Chancellor Angela Merkel after a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

Bavarian state prime minister Markus Soeder is seen on a video screen during a news conference of German Chancellor Angela Merkel after a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

German Chancellor Angela Merkel arrives for a news conference after a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

German Chancellor Angela Merkel and Mayor of Berlin Michael Mueller arrive for a news conference after a meeting with the leaders of the country's 16 federal states to discuss COVID-19 measurements in Berlin, Germany, June 10, 2021. Michael Kappeler/Pool via REUTERS

A worker in protective suit measures the body temperature of a man following the coronavirus disease (COVID-19) outbreak at a polling station during the presidential election in Ulaanbaatar, Mongolia June 9, 2021. REUTERS/B. Rentsendorj

Walloon Minister President Elio Di Rupo attends a news conference after a government meeting to announce the new coronavirus disease (COVID-19) related measures in Brussels, Belgium June 4, 2021. REUTERS/Johanna Geron/Pool

Walloon Minister President Elio Di Rupo attends a news conference after a government meeting to announce the new coronavirus disease (COVID-19) related measures in Brussels, Belgium June 4, 2021. REUTERS/Johanna Geron/Pool

Oliver Paasch attends a news conference after a government meeting to announce the new coronavirus disease (COVID-19) related measures in Brussels, Belgium June 4, 2021. REUTERS/Johanna Geron/Pool

Walloon Minister President Elio Di Rupo, Belgium's Prime Minister Alexander De Croo and Hilde Crevits attend a news conference after a government meeting to announce the new coronavirus disease (COVID-19) related measures in Brussels, Belgium June 4, 2021. REUTERS/Johanna Geron/Pool

Brussels Minister President Pierre-Yves Jeholet, Belgium's Prime Minister Alexander De Croo and Oliver Paasch attend a news conference after a government meeting to announce the new coronavirus disease (COVID-19) related measures in Brussels, Belgium June 4, 2021. REUTERS/Johanna Geron/Pool

Walloon Minister President Elio Di Rupo and Belgium's Prime Minister Alexander De Croo attend a news conference after a government meeting to announce the new coronavirus disease (COVID-19) related measures in Brussels, Belgium June 4, 2021. REUTERS/Johanna Geron/Pool

Hilde Crevits attends a news conference after a government meeting to announce the new coronavirus disease (COVID-19) related measures in Brussels, Belgium June 4, 2021. REUTERS/Johanna Geron/Pool

Belgium's Prime Minister Alexander De Croo attends a news conference after a government meeting to announce the new coronavirus disease (COVID-19) related measures in Brussels, Belgium June 4, 2021. REUTERS/Johanna Geron/Pool