In simple words, yes, online casinos are legal in India. Did you know that there are actually no central laws that prohibit online gambling in India? Well, currently Indian Government has no laws that make it illegal to gamble online in India.
The Public Gaming Act of 1867 is a central law in India that prohibits the establishment and running of land-based casinos. This act was developed in an era where there was no internet. Hence, it does not cover "online gambling" provisions in India.