I mean, he might want those things, but not want to have to do what it takes to achieve them. I wanna be a healthy weight, but I eat poorly and don't exercise. The difference is 80 million people aren't going to vote to give me the nuclear codes thinking that I could lose weight.
Of course, it's more likely that he's just saying he wants those things because who would be opposed to the idea of clean air and water as long as he doesn't talk about how to achieve it, and that supports what he does ultimately want, which is to be re-elected. He'd literally say anything he thinks will make that happen. Truth, consequences, morals, etc. are all things the little poor people have to worry about, not someone big and important like him.