Not pro but against wrongly removing gas (4)

I believe the answer is:

anti

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'not pro' is the definition.
('anti' is the opposite to 'pro')

I don't understand how the rest of the clue works.

(Other definitions for anti that I've seen before include "One who is against (something)" , "not favoured" , "Someone opposed (to a policy?)" , "Opposition member" , "Hostile" .)

I've seen this clue in the Sydney Morning Herald.

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