The India Gate war memorial in New Delhi, India, is pictured on October 17, 2019 (above) and on April 8, 2020 after a 21-day nationwide lockdown (below). Reuters reports that New Delhi is having "the longest spell of clean air on record."

Los Angeles, California is known for notorious smog and traffic. But the view on the bottom shows the San Gabriel Mountains on April 14, 2020. According to Business Insider, the improvement in air pollution is likely a result of fewer planes and cars on the roads.

The top photograph of New Delhi, India was on November 8, 2018 and the bottom one was taken on April 8, 2020. The staggering difference may be attributed to the world’s largest lockdown in the country of 1.3 billion people. All factories, markets, shops, and places of worship are now closed, most public transport suspended, and construction work halted as India asks its citizens to stay home and practice social distancing.

Milan was named Europe's most polluted city in 2008 and smog remains a recurring problem, according to BBC. But after the air pollution dropped significantly during the lockdown, the city announced an ambitious scheme to reduce car use after the quarantine ends. The bottom photograph of Milan was taken on April 17, 2020, while the top one was taken only four months ago.

The Grand Canal in Venice, Italy is seen here pictured on January 6, 2018 (top). But after the lockdown, new photos emerged of the canals looking crystal clear. The city's mayor told CNN that this was due to "less traffic on the canals, allowing the sediment to stay at the bottom." The bottom picture was taken on April 17, 2020.

Italy’s efforts to limit the spread of the coronavirus disease has led to a decrease of boat traffic in Venice’s famous waterways—as captured by the Copernicus Sentinel-2 mission. The top image, captured 13 April 2020, shows a distinct lack of boat traffic compared to the image from 19 April 2019.

Jakarta is known as one of the smoggiest cities in the world. But the same wreckage of a wooden boat pictured on July 26, 2018 and April 16, 2020 shows a night-and-day difference.

Last year, once again, India topped the charts of the world's most polluted places as home to 14 of the 20 cities with the most hazardous air. But Yamuna River in New Delhi, India, pictured on April 8, 2020 (bottom), looks unrecognizable compared to the same view from March 21, 2018.

The Jakarta Post reports that the air over the city has become increasingly polluted since 2018, hitting a new low in 2019, when the city was named the fifth-most polluted capital in the world.
But the air quality has improved since the social restrictions were issued in late March. The top picture shows Jakarta’s skyline on July 4, 2019 and the bottom one was taken on April 16, 2020.

CNN reports substantially lower levels of both noxious microscopic particulate (PM 2.5) and of nitrogen dioxide post-lockdown. In New Delhi, the PM 2.5 went down by 71% in a single week. The electricity pylons in New Delhi, India, were photographed on October 30, 2019 (top) and April 13, 2020 (bottom).

The local news source Dawn reported on April 02 that the quality of air in Islamabad was declining. But the current lockdown decreased the traffic, and visibility has dramatically improved. The view from the Daman-e-Koh point in Islamabad, Pakistan was taken on August 3, 2017 (above) and the recent one was pictured on April 20, 2020 (below).