Hyderabad Metro and NCMC Card

Recently travelled to Hyderabad for a short casual visit. Was unexpectedly suprised to realised that NCMC is still not supported or it is a very tightly coupled to limited banks(may be anyone using can share insights if any specific card has worked). Buying tickets online is still available and is easy. However, it still caught me by surprise. For a while I thought it was a card issue so I tested mine after returning home.