There is always a dispute over the origin of Banjo between Irish country musicians and American folk musicians. Both claim the origin of Banjo to their respective country. I tend go with the Africa. The native Africans have invented the maximum number of musical instruments made from myriad materials.
Irish folk music has great history. They play with several instruments and Banjo is one of them.
If you want to shop goodtime banjo, it is better you learn something about the shape and structure of banjo used a century ago. Contemporary banjo certainly is a modified version.
I never came across a banjo player in India. I think Mandolin played by a number of people in India comes close to banjo.