Mighty growth around Steppes originally a city (5)

I believe the answer is:

osaka

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'city' is the definition.
(Japanese city)

'mighty growth around steppes originally a' is the wordplay.
'mighty growth' becomes 'oak' (I am not sure about this - if you are sure you should believe this answer much more).
'around' means one lot of letters goes inside another.
'originally' says to take the initial letters.
The first letter of 'steppes' is 's'.
'oak' going around 's' is 'osak'.
'osak'+'a'='OSAKA'

Can you help me to learn more?

(Other definitions for osaka that I've seen before include "Port city of southern Honshu" , "Third most populous Japanese city" , "Large city and port in Japan" , "Kinki's capital" , "Japanese metropolis" .)

I've seen this clue in The Telegraph.

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