And nuclear, even fusion (when that shows up) isn't pollution free. Thousands of tons of radioactive materials are being stored because we have no way to dispose of it. Any fluids or materials that come in contact with the core become irradiated by neutron activation and we have no way of treating it other than putting it someplace out of the way for a very long time until it becomes less radioactive.
It is really minimal for fusion in relation to fission. In around 100 years there could already be no traces of radioactivity left depending on materials used for the reactor.
And we are just at the start of creating an efficient fusionreactor.