Old harbour in Indian city is suitable (9)
I believe the answer is:
opportune
'suitable' is the definition.
(I've seen this before)
'old harbour in indian city' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'harbour' becomes 'port' (I've seen this before).
'in' indicates putting letters inside.
'indian city' becomes 'pune' (I am not sure about this - if you are sure you should believe this answer much more).
'port' put within 'pune' is 'pportune'.
'o'+'pportune'='OPPORTUNE'
'is' is the link.
Can you help me to learn more?
(Other definitions for opportune that I've seen before include "Timely and convenient" , "Well-timed" , "Of time, suitable or favourable" , "fit" , "Timely, advantageous moment" .)