If you want access to books and materials, the Delhi Public Library and the Archaeological Survey of India offer free entry (closest metro station: Central Secretariat for the library and Rajiv Chowk for the Archaeological Survey). For more information, check out our library guide here. Membership for these libraries starts at around INR 20.
Timings: 8 AM to 8 PM for The Delhi Public Library and 9:30 AM to 6 PM for Archaeological Survey of India (closed on the weekend)