Marketplace abandoned by old Indian city (4)
I believe the answer is:
agra
'indian city' is the definition.
(I've seen this before)
'marketplace abandoned by old' is the wordplay.
'marketplace' becomes 'agora' (agora is a kind of marketplace).
'abandoned by' suggests deleting specific letters.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'agora' with 'o' taken out is 'AGRA'.
(Other definitions for agra that I've seen before include "Taj Mahal city" , "City famous for its Mogul architecture" , "includes Taj Mahal" , "Subcontinental city" , "North Indian city, former capital of the Mogul empire" .)