Most recent city trial (6)
I believe the answer is:
latest
'most recent' is the definition.
('late' can be similar in meaning to 'recent')
'city trial' is the wordplay.
'city' becomes 'la' (Los Angeles).
'trial' becomes 'test' ('test' can be a synonym of 'trial').
'la'+'test'='LATEST'
(Other definitions for latest that I've seen before include "Most up-to-date" , "Most recent or tardiest" , "State-of-the-art" , "hot bit of news" , "Of most recent date" .)