Stack scrubbers have made burning coal a very clean process.
Stack scrubbers will never be as clean as natural gas and nuclear is even cleaner. Plus spent fuel is 100% contained and stored in a tiny area. Coal not only always puts some pollution into the sky even with $100 million in scrubbers you cannot get away with the ash it creates. Toxic ash that never decays as it’s chemically toxic for all eternity. Look at the image at the top of the page it’s factual. One storage cask stops the generation of a huge amount of coal ash. Every gram of that ash is toxic and also contains more radioactive released to the environment than nuclear power would release by a million times. Coal ash is just piled up and allowed to leach into the watershed when not if the coal ponds leak they all will leak eventually.
https://www.reddit.com/r/nuclear/comments/144mm6e/each_nuclear_waste_cask_can_prevent_4_billion_lbs/