As part of Commonwealth day I ran around city (6)
I believe the answer is:
riyadh
'city' is the definition.
(capital of Saudi Arabia)
'as part of commonwealth day i ran around' is the wordplay.
'as part of' says the answer is hidden in the clue.
'around' is a reversal indicator.
'hdayir' can be found hidden inside 'commonwealth day i ran'.
'hdayir' written backwards gives 'RIYADH'.
(Other definitions for riyadh that I've seen before include "Saudi Arabian city" , "Saudi Arabia's largest city" , "Saudi Arabian capital" , "Middle Eastern venue" , "Capital of Saud Arabia" .)