Yes, playing online roulette as well as playing any other online casino game is legal in India. There are no federal or national laws in India that prohibit an Indian citizen from engaging in online casino gambling.
It is up to each state in India to decide if they want to legalise or prohibit gambling. That is why you have casinos operating in Goa and Sikkim, but a total prohibition of gambling in the state of Maharashtra. Most states, however, have not adopted any laws for or against online gambling.
Online gambling remains largely unregulated in India!
It is neither legal or illegal to gamble online in India. You will not be prosecuted for playing online roulette or any other casino game. This is the current legal status of online casinos in India.
Hopefully - in the future - we will have more clear rules on the subject of online gambling. If you are unsure about your state's regulations, we urge you to check your local legislation to find out if online gambling is permitted in your state.