Are they still development areas? (9)

I believe the answer is:

darkrooms

'are they' is the definition.
The definition suggests a plural noun which matches the answer.

'still development areas?' is the wordplay.
'still development' becomes 'dark' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'areas?' becomes 'rooms' (room is a kind of area).
'dark'+'rooms'='DARKROOMS'

I've seen this clue in The Guardian.

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