Devotee of "Bharata Natyam," a classical dance repertoire performed in the temples and courts of South India since ancient times, Arul Ramiah makes a plaintive "mudra" or hand gesture. Passed on by dancers from generation to generation, "Bharata Natyam" is enjoying a revival in India and among Indians of the diaspora like Ms. Ramiah, a Singapore attorney, graduate of Harvard University, and much-in-demand classical dancer.