Yoga is an ancient tradition that originated in India that was passed on by oral tradition and sacred scriptures. The sages passed on their knowledge to others and people adapted yoga to achieve consciousness. Nirvana Yoga School is a traditional Yoga School in Rishikesh, India certified by Yoga Alliance, USA.
https://www.nirvanayogaschoolindia.com/yoga-teacher-training-in-rishikesh-india