Do you know what 'Greenwash' means? It is a portmanteau (= a new word formed by joining two others) of green and whitewash. It means the actions of a company, which advertises positive environmental practices while acting in the opposite way.
For instance, when more money or time has been spent advertising being green, rather than spending resources on environmentally sound practices.
'Clean coal' is a good example of greenwash. Clean coal means coal chemically washed of minerals and impurities with the purpose of eradicating sulfur dioxide and other pollution. It designed to enhance the environmental acceptability of coal use.
Prominent environmentalists believe that the term clean coal is misleading: "There is no such thing as 'clean coal' and there never will be. It's an oxymoron".
Let us see it schematically. This is how the general model
'From Input to Output' looks like:
This is a more specific model when you have some Dangerous Phenomenon as an Input,
you fulfill your Action (PR move = Decoration),
and finally you receive your result (= you present the initial Dangerous Phenomenon as a Friendly Phenomenon instead):
Now you specify the initial general model even more. The Input (= Dangerous Phenomenon) turns to be "Coal", the Action (= Decoration) is Greenwash, and the Output (= Friendly Phenomenon) is "Clean Coal":
This is a simple PR tactics of giving something dangerous a more friendly name.