Hey Zameer,
I'm so happy to see another Indian around. Inspite of Tarot's widespread in India I have so far come across only four, including me, on this forum.
I'm not form Mumbai so won't be able to suggest any shops here. You can check with a-shikhs, a member of this forum. She has decks she trades from time to time on tarot trading forum.
There is also an Indian website,
www.tarotindia.com, you can check with Swati Prakash owner of tarotindia. She is from Mumbai and may be able to help you.
I usually get my decks from US whenever some of my friends are coming down. I place the order online and get it shipped to their US address and they bring my decks to India.
Another option is to check with bookshops if they can order for you. Odessey did that for me once. They have tie ups with the big publishers and they can get the deck but you don't get discounts on them.
Good Luck!!!
Lov,
May