It would be interesting to be able to adjust some of the polices of your vassals. Of course you would have to pay any fees. That way if you are getting lots of pollution spillover, and you tried a peaceful way of stopping it, you could stop it with the blood and iron of your cannons.
I like the idea of forced Industry Style change, though. Perhaps make it an advanced spy mission. Change your opponent's industry style to Green Just have it be something like "Incite Revolt" only it's your spy starting a workforce rally of some sort, where the workers demand from the government a change in industry style (to whatever they choose, or perhaps just a random other possible option)... Have it cost something like... Oh, here's an idea. Make it cost 1 Food + 1 Refined material of whatever that area mines? Or maybe just 1 Food + 1 material that area mines. Sort of like a "I work here, really, see, look, I have some bauxite to prove it!" thing?
Yeah interesting idea whoever made it. Yeah pollution is a problem and could start to affect the climate of the world. I say if people do not meet the Kyto Accord, that we force them through BLOOD and IRON.