Rubbish in derelict housing block (6)
I believe the answer is:
hinder
'block' is the definition.
('hinder' can be a synonym of 'block')
'rubbish in derelict housing' is the wordplay.
'housing' indicates a hidden word (part of the clue houses the answer).
'HINDER' is hidden in the letters of 'rubbish in derelict'.
(Other definitions for hinder that I've seen before include "Place obstacles in front of" , "stop" , "Prevent, obstruct" , "Obstruct, present an obstacle" , "Delay progress, obstruct" .)