Originally Posted by
PiperAtGatesofDawn
They will accept your YYZ-DEL BP. So keep that handy. Don't worry about the D's & T's and what nots. I'd buy at DEL because I'd get better choices there.
Also while I've only flown to COK a couple of times I've really not seen a duty free there.

So it must be really hidden really well or I've just completely missed it. I do remember something being there before picking up luggage, but not before immigration.
I had sent an email to Delhi duty free customer service asking about the same.
They replied to my email after 3 weeks, they say they can sell alcohol only to "passengers who are travelling internationally with an international boarding pass" .
They did not specify if that meant passengers who depart to an international destination or passengers arriving from an international destination ( and transiting to domestic destination)