What do Bollywood dancers wear?

On Sunday morning a little before 11 a.m., the tiny front office at NDM Bollywood Dance Studios in Artesia, Calif., was packed with women waiting for the biweekly “Bollywood Cardio” class to start.

Over the beat of Indian music from inside the studio, choreographer Nakul Dev Mahajan’s voice was suddenly loud — and his tone was unmistakably critical. The problem was not a missed hand gesture or out-of-synch spin, but rather social media.

“You’re in the spotlight now, " Mahajan reminded his professional company of young dancers. "What you post on YouTube reflects on me and this studio.”

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The 38-year-old instructor has been at the center of some of Bollywood’s biggest U.S. moments. In 2008, he choreographed the first Bollywood routine for the popular television show, "So You Think You Can Dance, " five months before the film "Slumdog Millionaire" had many Americans attempting to sway their heads Indian-style to “Jai Ho.”

Last year, he brought Bollywood to both the White House for First Lady Michelle Obama’s Diwali celebration and the Miss America pageant, where his moves helped Nina Davuluri spin her way to the crown.

But most days of the week, Mahajan can be found at his studio in L.A.’s Little India, giving Bollywood lessons to kids, teens and adults. He also leads the decidedly less traditional “Bollywood Cardio” class, which attracts the widest audience, according to NDM staff.

Many of these participants are drawn to Bollywood dance by the upbeat music, sparkling costumes, and fitness factor, but they probably can’t tell a flag mudras from a flowering lotus mudras.

Mudras are the very precise hand gestures used in Bollywood dancing to convey a specific meaning. They also are a clear reminder of the modern art form’s roots in one of the oldest, most spiritual dances in Indian culture: Bharata Natyam.

This classical dance originated in southern India thousands of years ago and was initially performed in Hindu temples to honor the gods. Though it later moved to the stage, the movements are still associated with particular deities and their stories.

"In Bharata Natyam you learn combinations that are literally taken from the Vedas, our religious books. It's like taking a chapter from the Bible and saying, 'I'm going to turn it into a dance, '" explains Mahajan.

Choreographed dances in early Bollywood films were heavily influenced by Bharata Natyam, as well as regional Indian folk dances and Kathak, a classical form that blends Hindu and Muslim cultures.

But as Bollywood incorporated new styles, like disco and hip-hop, its religious ties became less obvious: "It's been so watered down over the years that no one connects [Bollywood and Bharata Natyam]. Do we know in 2014 that we're doing something religious? Probably not, " says Mahajan.

Still, the classically-trained Indian dancer is not willing to forgo tradition entirely, even in his informal "Bollywood Cardio" class. Because many of the movements stem from temple dances, participants are required to do the workout barefoot.

"I find it really awkward to do a Bharata Natyam gesture with shoes on. It's a temple form of dance, and we don't wear shoes in our temples. That’s why I always ask people in my classes to take their shoes off. It's respectful."

This story is one in an occasional series of reports by students taking part in a class of the USC Annenberg Knight Program on Media and Religion, headed by Diane Winston. Thanks to a grant from the Luce Foundation, Annenberg students have covered global religion, culture and politics for the past four years. This spring, students will report and write on Southern California's Indian community and travel to Pune and Mumbai in March, where they will cover religion, economics and politics.