CBSE Class 10 Answered
Take solar and wind. You have to build the cells and turbines. Even if as clean as possible in manufacturing there is pollution. Cells and turbines have to be replaced. Also, these places are not 100% efficient. They require wire, lubrication, manpower,and other things. There is one wind farm in England that used more electricity than it produced. Also, wind turbines harm birds, they produce a hum noise that is noise pollution, and the sites are pollution themselves. They are called a visual pollutant. They have also been banned in some cases, because the best location was also the home of an endangered rat, and the rat won.
Lastly wind and solar require power plant backup. Unlike coal, nuclear, and crude, wind and solar do not work 24 hours per day, so you have to have these other polluting sources. Since they require these for a continuous grid, they are polluting in the big picture.