In Venice, Italy, without a gondola or tourist in sight, a jellyfish was spotted wading through the city’s famous canals. In New Delhi, India, the city’s toxic air pollution, once visible from space, has begun to clear. Along Amtrak’s Northeast Corridor route, from Maryland past Boston, air pollution fell 30%, according to NASA—the cleanest it has been since the agency started measuring. Los Angeles is experiencing its longest stretch of “good” air quality since 1995. Carbon emissions in China fell nearly 25% when manufacturing shut down to contain the spread of coronavirus.