Is this even legal?

Laws varies by countries so it might illegal in some while being legal in others. Aren't you from India I expect more from people from that country in term of sheer volume of maximization of compute data that you should already have the answer to your question yourself.

Even if it's illegal in your country, the law enforcement probably ignores it, because there are millions who watch loli hentai everyday and they can't punish that many people for something as insignificant as watching animated porn, because it's not causing any real harm.