Many of the heavily-SEO'd "Top 10 Yoga Schools" lists are paid placements, not reviews. Verify a school's registration directly on yogaalliance.org before paying, not on the school's own site. If you just want to try yoga, short drop-in classes at an established ashram are cheap and need no research.
The 200-hour teacher training format traces back to the U.S.-based Yoga Alliance, founded in 1999, which set the first standardized international benchmark for teacher certification (RYT-200) covering technique, anatomy, philosophy and teaching methodology at a time when no formal regulation of yoga instruction existed. Rishikesh's emergence as the epicenter for these courses built on its older reputation as a center for sages and yogis, reinforced in the modern era by events like Parmarth Niketan's International Yoga Festival, launched in 1999 with the Uttar Pradesh tourism department. Dozens of registered yoga schools clustered in Tapovan now run back-to-back 200-hour certification cycles for international students, cementing the neighborhood's identity as ground zero of the global yoga-teacher-training industry.