Out running in NYC rain, struck by the century-long triumph of environmental regulation that allows air so clean in a huge city. We should celebrate environmental success to demonstrate the power of government regulating for public good & driving technological change. pic.twitter.com/XqxJMrqjCq

PM2.5 AQI is 50, it's 200 in Dhaka where I was last week. (Of course this is air pollution not climate, and of course there's a blowhard at the top trying to dismantle it, but for now just enjoy the reasonably clean air)