Area of the Med -- one in Asia being developed (6,3)
I believe the answer is:
ionian sea
'area of the med' is the definition.
'ionian sea' can be an answer for 'med' (I've seen this before). I am not sure about the 'area of the' bit.
'one in asia being developed' is the wordplay.
'being developed' indicates an anagram.
'one'+'in'+'asia'='oneinasia'
'oneinasia' with letters rearranged gives 'IONIAN SEA'.
Can you help me to learn more?
(Other definitions for ionian sea that I've seen before include "Waters west of Greece" , "Med" , "Corfu location" , "Waters surrounding Corfu and Paxos" , "Greek waters" .)