Indian song vs Assamese song!

One day a friend of mine was going with me in my car. He is a Hindi-speaking guy from north India. I was playing an Assamese music CD of Zubin Garg in my car audio system. I offered to change the Assamese song; but he said that he'd like to hear that. After a few minutes, he told me that Assamese songs are as good as Indian songs! I was a bit surprised. What did he mean by Indian songs? I asked him if he meant Hindi songs. He corrected himself and said that he meant Hindi songs. I wanted to argue with him whether he thought that Assam is out of India and in that case I'm a foreigner! I decided not to argue.