Awful racket in road crossing Hyde Park (6,3)
I believe the answer is:
rotten row
'road crossing hyde park' is the definition.
(road near Hyde Park in London)
'awful racket' is the wordplay.
'awful' becomes 'rotten'.
'racket' becomes 'row' (both can mean a noisy disturbance).
'rotten'+'row'='ROTTEN ROW'
'in' is the link.
(Other definitions for rotten row that I've seen before include "Once fashionable avenue for riders in London" , "making foul noise?" , "Horses here" , "Capital place for riding" , "Where to see riders" .)