The clean air act is an act trying to make the air cleaner. Which could be effective to out future. So far, they only did a little. It is also really pricy to do it can take billions of dollars. The government isn’ t helpful enough. It is really hard to do something.
What you can do
Even through the whole system is complicated, an human can do something. You can use a car less. Start riding your bike and walking to destinations more. Use resource wisely and recycle. One person can do a big thing.