NEW DELHI, June 21, 2018 (News Wires) - From the Himalayan region of Ladakh to the deck of an aircraft carrier, tens of thousands joined Indian Prime Minister Narendra Modi on Thursday to celebrate the fourth International Day of Yoga, with a few wearing masks to highlight poor air quality. Modi pushed for the annual event to be held worldwide after winning power in 2014, with the lifestyle industry centered on the ancient physical and spiritual discipline estimated to be worth around $80 billion. Pictures on social media showed participants braved rising mercury levels and unhealthy air quality in some places to spotlight yoga, India's cultural export to the world. Countries such as Afghanistan, Japan and Peru held yoga sessions, while Australia and South Africa celebrated on Monday. In India, more than 50,000 people joined Modi in performing yoga in the lawns of Dehradun's Forest Research Institute, in the Himalayan foothills of the northern state of Uttarakhand.