To the best of my knowledge,
a) If the quarter provided to you is unlivable, then the GE must put it under maintenance or special repair, else your refusal to take that quarter will relegate you in the roster. Alternatively, depending on which govt service you belong to, an appropriate authority can give you an "unhygienic certificate" for the allotted quarter.
b) Once GE puts the quarter into maintenance / special repairs, or you get an "unhygienic certificate" then the quartering officer (or the relevant controlling authority) will have to cancel your allotment and give you an alternative accommodation, if available.
c) As long as there are vacant accommodation available (excluding those under special repairs / maintenance) the quartering officer will allot you one (even if below scale). Essentially, no govt quarter will be left vacant (and employees allowed to claim HRA) if there are people waiting in the accommodation roster; because quartering officer will have to justify why he is recommending HRA when quarters are lying vacant.
I hope I have answered your question.
19th April 2018 From India, Kochi
You may take steps to expedite that decision by getting a certificate from the civil engineer about the condition of the quarters and submitting it to the authorities. You have the option to approach the CAT, but it involves some expenses unless you would be able to appear party-in-person.
21st April 2018 From India, Kochi