Then, one day, he came across an article on the health benefits of laughter, and was amazed. Rigorous scientific studies kept concluding the same thing: it reduces stress, increases oxygen flow to the brain and exercises the internal organs, among other things.

Kataria was dismayed that in normal day-to-day interactions, people don't laugh nearly enough.

"It's not always socially acceptable to have a big, very big, belly laugh. But those types of laughs give you the most benefits."

So, he and his wife Madhuri decided to set up a laughter club in Mumbai.

The rest, as they say, is history.

Today Kataria and Madhuri run Laughter Yoga International, which has thousands of clubs spread around the world in over 60 countries.

It's truly an Indian phenomenon gone global.

Here, an interview with Dr Kataria.

Here is some video footage from one of his famed classes!