One of our favourite bookstores in the city, Bahrisons Booksellers is offering delivery of books in Delhi and Gurgaon through their Saket (011-46152700), Khan Market (011-24694610, and Galleri Market (+91 7678609336) stores. In-store browsing and pick-up isn't allowed yet, and delivery is subject to availability. You can call the above numbers to order your books and transfer money when the orders are confirmed.
They'll be delivering in all non-containment zones in Delhi and in Gurgaon, delivery is limited to Sushant Lok, Sectors 29, 23-39, 45, 49-66, Golf Course Road, DLF Phase 1 &2 and Baani Square. However, we do recommend calling them up and asking them if delivery to areas other than these is possible. It just might be your lucky day!