Just my opinion, but when you look at what's happening in southern California as we speak about it, the pollution being produced by the fires will likely be a greater issue in the next few years than any "clean vehicle mandate" would have resolved...
I'm not just thinking about the smoke/ash from wood burning, but the petroleum, chemicals and asbestos that is being released into the air. That can't be "cleaned up from the air, water and soil" by any mandate. Mother Nature has a way of doing what she wants without regard to "regulations"...
We've all got a "mess on our hands" and by "we" I mean all of the US, not just those living within a hundred miles of the fire....