RANCHI, INDIA (AFP) - Indian Prime Minister Narendra Modi led the way for International Yoga Day on Friday (June 21), performing sun salutations and other flexible feats in a mass session with an estimated 30,000 other devotees of the discipline.

Yoga Day, observed mostly in India but also worldwide on the Northern Hemisphere's longest day, was Mr Modi's idea. It was adopted unanimously by the United Nations General Assembly in 2014 and first took place in 2015.

Mr Modi, whose moves in Ranchi in northern India were live streamed on the Internet, this year took to business networking website LinkedIn to extol yoga as a panacea for stress and even hate.

"In a world where ideologies of hate can potentially divide brother from brother, yoga stands as a unifying force," Mr Modi wrote. "In a time where health ailments, especially stress-related ailments are rising, yoga is giving relief and joy."

The theme of this year's Yoga Day, the fifth, is "climate action", and Mr Modi said yoga can "foster oneness... with all the flora and fauna with whom we share our beautiful planet".

In recent days, Mr Modi, 68, fresh from a landslide election victory, has also posted videos to social media featuring an animated version of himself performing different yoga postures.

Elsewhere in India, armed forces personnel were due to practice downward-facing dogs and other poses on an aircraft carrier in Mumbai, while in Mysore, a golf course was set to became a mass yoga location.

Yoga has boomed in recent decades, with millions - perhaps up to 300 million - practising it regularly, although in the West it is often more of a physical than a spiritual activity.

Among the more unusual forms that have sprung up are "hoga" (yoga on a horse), "noga" (nude yoga), "doga" (yoga with a dog) - and Harry Potter yoga complete with a "Downward Dumbledore".