Commentary If you’ve noticed that your grass grew a little fuller and faster this year, it could be due to the pandemic lockdowns. People drove a lot less. They went to work less. This shut down polluting factories around the world, and decreased smog. More sunlight got through to the plants, and that made the plants grow more. Maybe it required mowing the lawn a couple more times over the summer if you’re the kind of person who likes a trim yard. The biggest effects may have been in China, the United States, and India, which are the world’s biggest polluters on an absolute basis. Data on emissions per hectare, which should be a good predictor of effects on plant life, are difficult to find. Such data would, I think, show that the effects of a given intensity of lockdown would be greatest in India, which is probably one of …