While the consensus (and I agree) is that you are legally allowed to do a INT-INT transfer at DEL w/o a visa, keep in mind that you'll need to convince the BA check-in person that you are able to travel to India without a visa. This may be the hard part. (I have no experience with this, but I've seen and heard of check-in agents refusing to check you in because you don't have the visa they expect you to have, even if that visa is not required in your case.)