One can renounces one's U.S. citizenship in the presence of U.S. official entities, in his case the U.S. consulate. Mind you he OP has not claimed the U.S. citizenship, he has claimed U.S. birth. There is a reason for that. He cannot claim U.S. citizenship through birth ans yet satisfy the Indian law. It is impossible for someone with an Indian passport to be a dual citizen. Even the U.S. officials do not look at dual citizens in a very positive light these days. I know several people who have had to give up their "other" citizenship.