World Laughter Day was established in 1998 by Indian yoga master Dr. Madan Kataria, who is also the founder of the worldwide laughter yoga movement. /VCG Photo

Laughter yoga, also known as Hasyayoga in Hindi, is a yoga practice involving free body movements accompanied with voluntary laughter. /VCG Photo

Dr. Kataria, a family doctor, created the practice based on the belief that voluntary laughter can transform into positive emotions and enhance psychological wellbeing. He has even proposed putting laughter yoga on the school curriculum. /VCG Photo