Domain Name Registration?

Suppose there is a US site blahblahcasino.com and I for genuine reasons register same site in India as blahblahcasino.in then will this be illegal? Please help.

It's most likely legal to purchase the domain name since it's on the web and for sale by a licensed registrar, however the name "blahblahcasino" may be copyrighted or otherwise protected and you would be unable to use it.