I just got the game with xbox game pass and I played the first game which was created for me in the tutorial,( I selected that I have played historical strategy before). After a while I had outmaneuvered diplomatically, culturally and religiously the only other nation on my continent and also the most powerful nation in the game by doing the "oppresing the faithful" and similar which meant that I managed to nick several of their cities and got a stupid amount of resources. I reached the contemporary era in like 1550 or so and then I choose soviet and I began to build the armaments factories which meant that I got pollution way too early. Then when I got coal power and factories my pollution was already quite high and then it exploded. I researched the first techs which would allow reducing pollution about 10 turns before my game ended because of too much pollution.

What I suggest is that all forest add a constant pollution reductions, as well as a major one when you have just built them. Also maybe that untouched snow tiles have a slight constant reduction. Also that all grass have a slight pollution reduction as well. I believe this would be good as to prevent pollution spiraling out of control early since it would allow you to contain pollution whitout those techs.