Gambling in India is not allowed everywhere, but in Goa, Daman and Sikkim casinos operate officially. However, each region has its own rules, peculiarities of licensing and regulation. To understand this issue, I advise you to read the article at
https://theceoviews.com/goa-daman-and-sikkim-the-indian-casino-trio/. It explains how local authorities control casinos, what laws apply to operators and what guarantees players receive.