Thousands in India are gearing up for the country's first-ever International Day of Yoga, a holiday proposed by Prime Minister Narendra Modi last year in an effort to rebrand and promote the ancient practice. The event is planned for June  21, when an estimated 45,000 people are expected to participate in a 35-minute yoga routine. But religious minorities, including many Muslim groups, have raised concerns over the holiday, pointing specifically to yoga's close ties to Hinduism. Some have called for the removal of "surya namaskar", commonly known as the "sun salutation", from the routine, saying it was against their beliefs to salute the sun.