New York Times: Back in 1970, Los Angeles was known as the smog capital of the world a notorious example of industrialization largely unfettered by regard for health or the environment. Heavy pollution drove up respiratory and heart problems and shortened lives. But 1970 was also the year the environmental movement held the first Earth Day and when, 45 years ago this month, Congress passed a powerful update of the Clean Air Act. (Soon after, it was signed by President Richard Nixon, and it was followed by the...