Fun little card game! It definitely seems like the special cards have a few kinks. In particular, I ran into the same softlock as some others, where I had one card left that I couldn't play. I also noticed that one of the CPUs seemed to play a red skip on top of a blue card (when the pollution was 0).
But, I do think the card rules seem to work pretty well overall! One round I won, I had an interesting combination of special cards, so I had to try to manipulate the pollution level in both directions. It seems like a nice variety of gameplay scenarios can crop up with this rule set--for example, another game I had mostly blue cards, which was interesting as that round was much more based on what the CPUs did to the pollution level.
One note on accessibility, that I thought of while rating: it seems like the only indication of which cards a special card is allowed to be played on is color. I wouldn't be surprised if the red and green skip cards were hard to tell apart for someone who's red/green colorblind.