Damn, it's hot. So hot and so humid that Cincinnati has declared a "smog alert."
Declaring a smog alert doesn't actually do much, other than that the authorities urge you to not mow your lawn and avoid driving during the heat of the day, when the sun cooks pollution into a nasty mess. Whether average citizens obey the warning is debatable.
If we don't improve the air quality, we risk losing federal money for road projects. To address the situation, several years ago the area started an auto emissions testing program.
Every other year you go a testing place and they your car's exhaust fumes and emissions system. If you flunk (meaning your car is putting out too many pollutants and isn't operating as it should), you can't renew your car's registration/license. So if you drive your car, it's illegal.