Call up process to cut carbon emission (9)

I believe the answer is:

emanation

'emission' is the definition.
(synonyms)

I can't explain the rest of the clue.

(Other definitions for emanation that I've seen before include "Something flowing out from a source" , "Pouring out" , "Something issuing from a source" , "Something given off" , "produce radioactive gas" .)

I've seen this clue in The Guardian.

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