Conflict almost tore apart densely populated area (6)
I believe the answer is:
warren
'densely populated area' is the definition.
(I've seen this before)
'conflict almost tore apart' is the wordplay.
'conflict' becomes 'war' (war is a kind of conflict).
'almost' means to remove the last letter (most of the word but not all of it).
'tore apart' becomes 'rent' (I've seen this before).
'rent' with its last letter taken away is 'ren'.
'war'+'ren'='WARREN'
(Other definitions for warren that I've seen before include "densely populated district" , "Rabbit colony" , "Connecting burrows" , "Rabbit home" , "Labyrinth of burrows" .)