Although not in itself a religion, Yoga is deeply rooted in Hinduism. In the west, however, Yoga is practiced, usually, as a wellness exercise regimen with no religious content at all. Is Yoga a religion? It is if you pursue its roots and connect it to the religious thought at its source. Otherwise, it is merely a form of bodily exercise and meditation routines which may be of some value to its practitioners in physical flexibility and meditative discipline.
I hope you have found this helpful.
God bless,
Mike