Coal is a nonrenewable resource. Therefore, it can't be used infinitely. Coal also has a giant carbon footprint and releases a lot of greenhouse gasses. As a result, coal releases more carbon dioxide than any other fossil fuel used. This is demonstrated in the photo below.
Coal is clearly not clean at all due to the carbon dioxide, sulfur dioxide, and nitrogen oxide emissions released into the air.
Please, watch this video on clean coal.
https://www.youtube.com/watch?v=W-_U1Z0vezw
Please, watch this video on clean coal.
https://www.youtube.com/watch?v=W-_U1Z0vezw