Popular street ruined by diversion (8)
I believe the answer is:
interest
'diversion' is the definition.
(interest is a kind of diversion)
'popular street ruined by' is the wordplay.
'popular' becomes 'in'.
'ruined' is an anagram indicator.
'by' says to put letters next to each other.
'street' with letters rearranged gives 'terest'.
'in'+'terest'='INTEREST'
(Other definitions for interest that I've seen before include "importance" , "Care" , "Fascinate" , "Profit" , "Deposit account gain" .)