To mark International Day of Yoga, Indian Prime Minister Narendra Modi took part in a mass session. An estimated 30,000 people performed sun salutations and other flexible feats. Yoga Day is Modi's idea. It is observed mostly in India but also worldwide on the Northern Hemisphere's longest day. It was adopted unanimously by the UN General Assembly in 2014 and first took place in 2015. The theme of the fifth edition of the event is "climate action." Modi says yoga can "foster oneness with all the flora and fauna with whom we share our beautiful planet."