... yet still all the choking smog in Beijing and other Chinese cities.

I'm not sure what point you're trying to make, but it's clear that China is a serious polluter, and I fail to understand why more stringent standards weren't applied for China and other serious polluters in Asia.

Your argument suggests that it was to allow for Chinese GDP growth, however, why is GDP growth okay for China (at the expense of smog in Beijing and other places), but similar growth in the US is completely unacceptable? Ignoring the question of whether we can actually trust the Chinese, do you even see the irony in this logic?

To conclude, I don't think the US is going to go back to the pollution levels of the 1950s.  Cheap natural gas is quickly replacing coal, and several states have redoubled their commitment to the Paris Climate Agreement.

It's all too easy to criticize Trump, however, I wish environmentalists would be equally as critical of countries like China and India.  I have yet to see that.