Police officer severe with southern areas (9)
I believe the answer is:
districts
'areas' is the definition.
(I have seen 'Areas of jurisdiction' mean 'districts' so perhaps 'areas' could also mean 'districts')
'police officer severe with southern' is the wordplay.
'police officer' becomes 'DI' (abbreviation for Detective Inspector).
'severe' becomes 'strict' (I've seen this in another clue).
'with' is a charade indicator (letters next to each other).
'southern' becomes 's' (abbreviation).
'di'+'strict'+'s'='DISTRICTS'
(Other definitions for districts that I've seen before include "Areas of jurisdiction" , "Regions, administrative areas" , "Certain areas, regions" .)