I was first back round hot metropolis (5)
I believe the answer is:
delhi
'metropolis' is the definition.
(Delhi is an example)
'i was first back round hot' is the wordplay.
'was first' becomes 'led'.
'back' says the letters should be written in reverse.
'round' is an insertion indicator.
'hot' becomes 'h' (abbreviation eg on taps).
'i'+'led'='iled'
'iled' backwards is 'deli'.
'deli' placed around 'h' is 'DELHI'.
(Other definitions for delhi that I've seen before include "Old city of north central India" , "Indian state" , "Indian territory" , "Ancient city" , "Capital at one time" .)