Pollution declines amid coronavirus lockdown

A general view of freeways leading into downtown Los Angeles after California issued a stay-at-home order in Los Angeles, California, March 23, 2020.  REUTERS/Lucy Nicholson

A combo shows the India Gate war memorial on October 17, 2019 and after air pollution levels started to drop during a 21-day nationwide lockdown in New Delhi, India, April 8, 2020. REUTERS/Anushree Fadnavis/Adnan Abidi

Clear water is seen in Venice's canals due to fewer tourists, motorboats and pollution in Venice, Italy, March 18, 2020. REUTERS/Manuel Silvestri

A combo shows a boat on the banks of the river Yamuna on March 21, 2018 and after air pollution level started to drop during a 21-day nationwide lockdown in New Delhi, India, April 8, 2020. REUTERS/Adnan Abidi

An empty freeway intersection is seen after Los Angeles’ stay-at-home order caused a drop in pollution in Pasadena, near Los Angeles, California, April 20, 2020.  REUTERS/Lucy Nicholson

A combo shows buildings on November 8, 2018 and after air pollution level started to drop during a 21-day nationwide lockdown in New Delhi, India, April 8, 2020. REUTERS/Anushree Fadnavis/Adnan Abidi

A view of the city of Athens with the Acropolis hill seen in the middle in Athens, Greece, April 14, 2020. REUTERS/Alkis Konstantinidis

A combination picture shows a man walking on top of the wreckage of a wooden boat as smog covers the sky in North Jakarta, Indonesia, July 26, 2018, (top) and a view of the same location, April 16, 2020. REUTERS/Beawiharta/Willy Kurniawan

Clear water is seen in Venice's Grand Canal due to fewer tourists, motorboats and pollution ahead of Earth Day in Venice, Italy, April 16, 2020. REUTERS/Manuel Silvestri

A combination picture shows birds flying next to electricity pylons on October 30, 2019 and after air pollution level started to drop during a 21-day nationwide lockdown in the old quarters of Delhi, India, April 13, 2020. REUTERS/Adnan Abidi

Clear water is seen in Venice's canals due to less tourists, motorboats and pollution ahead of Earth Day in Venice, Italy, April 16, 2020. REUTERS/Manuel Silvestri

A combination picture shows a view of the Italian Alps amid dense fog and smog January 8, 2020, (top) in Milan, Italy, and the same view, April 17, 2020. REUTERS/Flavio Lo Scalzo

A combination picture shows people looking at Islamabad, Pakistan, from the Daman-e-Koh viewing point, August 3, 2017 (top) and the same location, April 20, 2020. REUTERS/Faisal Mahmood/Saiyna Bashir

Clear water is seen in Venice's canals due to less tourists, motorboats and pollution, ahead of Earth Day in Venice, Italy, April 16, 2020. REUTERS/Manuel Silvestri

A combination picture shows high-rise buildings in Jakarta, Indonesia amidst smog, July 4, 2019, (top) and the same view, April 16, 2020. REUTERS/Willy Kurniawan