Half hour stoppage in town (5)
I believe the answer is:
urban
'in town' is the definition.
(I've seen this before)
'half hour stoppage' is the wordplay.
'half' means to take half the letters.
'stoppage' becomes 'ban'.
'hour' with half the letters taken is 'ur'.
'ur'+'ban'='URBAN'
(Other definitions for urban that I've seen before include "Had this description of town" , "Relating to cities" , "Living in a city" , "Relating to a city/town" , "Municipal" .)