It is not a religion. Yoga is a vast collection of spiritual techniques and practices aimed at integrating mind, body and spirit to achieve a state of enlightenment or oneness with the universe.
Yoga is delivered via many different paths that will vary from yogi to yogi, from region to region and from country to country. Regardless, the different paths of yoga emphasize different approaches and techniques, but ultimately lead to the same goal of unification and enlightenment.
Though yoga’s ultimate aim is lofty, its essence is practical and scientific as it emphasizes direct experience and observable results – it should be a practice of personal inquiry and exploration for each individual student.