Buddhism - Is it a religion?

I disagreed from the very beginning, after understanding some Buddhist philosophy, that it is not a religion. In my opinion, it is not a religion but a lifestyle or administration under which Buddhist teaching is practised. Please clarify why it is classified as a religion. **PS**: I have met many people specially from Nepal, who claim as a Buddhist monk but yet they don't seem to practice any Buddhist norms. And they even call me 'nastik' (one who don't believe in religion)