Impoverished neighbourhood preferred flat's interior (6)
I believe the answer is:
favela
'impoverished neighbourhood' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'preferred flat's interior' is the wordplay.
'preferred' becomes 'fave' (short for favourite).
'interior' means to look at the middle letters.
The middle of 'flat' is 'la'.
'fave'+'la'='FAVELA'
Can you help me to learn more?
(Other definitions for favela that I've seen before include "Shanty town, especially in Brazil" , "(Brazilian) shack, shanty town; Alf, Eva (anag.)" , "Brazilian slum" , "Ramshackle town" , "Shantytown in Brazil" .)