Depends how one defines "polluting."<quoted text>
I provided a link. You can go back and find it.
However, it is a FACT that coal plants are the most polluting of all power stations.
Modern coal fired plants remove particulates, sulfur oxides, and nitrogen oxides.
One could easily argue that solar power plants cause far more permanent damage to the environment because of the vast amounts of land involved and their frequent location in desert areas that have very fragile ecosystems that cannot recover once disturbed.
Wind turbines also have significant environmental effects, including killing large numbers of protected bird species.
And the negative effects of hydropower projects such as the Three Gorges Dam in China are obvious.