The International Day of Yoga has been celebrated across the world annually on June 21 since 2015, following its inception in the United Nations General Assembly in 2014.. Yoga is a physical, mental and spiritual practice which originated in ancient India. The Indian Prime Minister Narendra Modi, in his UN address in 2014, had suggested the date of June 21, as it is the longest day of the year in the Northern Hemisphere and shares a special significance in many parts of the world.