Countries in which Bitcoin is banned (as of July 2018) one way or another: India, Algeria, Bolivia, Ecuador, Bangladesh, Nepal, Cambodia, Indonesia, Pakistan, China, Iceland;
Countries in which Bitcoin is legal: the US, Canada, Australia, Mexico, Nicaragua, Costa Rica, Kyrgyzstan, Cyprus, UAE, Israel, Japan, Switzerland, Malta;
Countries in which Bitcoin is not regulated: all the rest.
No country or Central Bank can ban something which is already decentralised. India's finance minister in his budget speech of 2018 had stated that Bitcoin is not a legal tender which means Bitcoin cannot be used like a fiat currency but buying and selling Bitcoin is still prevalent in many countries including those where it has been allegedly banned.