Mumbai, May 19 -- Every morning, Mumbai's local trains are packed with people heading to work. In the middle of all the hustle, however, something special has been happening. Some passengers close their eyes, sit straight, and engage in light breathing and stretching exercises. This is Mumbai's most unusual yoga class, which happens inside moving trains.

This idea came from Ruchita Shah, the founder of Heal-Station, a group that promotes wellness. She started this on International Yoga Day in 2017 as a small experiment. Today, it has become a large movement with over 100 volunteer yoga teachers and thousands of commuters joining in. "People are surprised when we say we do yoga in crowded trains," Shah said. "But we show them that it is p...