Students at a camp in Hyderabad, India, were bent on getting the downward-facing dog pose right ahead of International Yoga Day.

Today is the fourth edition of the annual event, and will be marked the world over with mass yoga and meditation sessions, as well as seminars and workshops on this centuries-old practice.

Indian Prime Minister Narendra Modi is expected to lead a crowd of more than 60,000 people in an early morning exercise session in the northern Indian city of Dehradun.

Persuading the United Nations to create International Yoga Day has been seen as a feather in Mr Modi's cap, and a triumph of soft power.

The Prime Minister, who is a keen practitioner of yoga, has spearheaded initiatives to promote the discipline and other traditional practices since his Hindu-nationalist government came to power in 2014.

Indian scholars believe yoga dates back 5,000 years, based on archaeological evidence of poses found inscribed on stones and references to yogic teachings in ancient Hindu scriptures.