Where is everybody?

The efforts to stem the spread of the coronavirus have also offered us a rare experiment: We can see our cities for the first time without the choking traffic, dirty air and honking horns that have so often made them intolerable.
The coronavirus has forced extreme changes in our behavior in just days. And we’re already seeing the impact of those changes: On Monday, for example, Los Angeles had the cleanest air of any major city in the world.