It’s virtually unknown in the consumer lighting market. But NTL, the ₹700-crore company Arun Gupta created with his brother Praveen, can safely claim to be at the heart of most fluorescent tubes and CFL lamps made in India, a position it holds as the largest maker of electronic drivers and ballasts that run modern lights. To the uninitiated, a ballast regulates the current in a fluorescent lighting system. With around 5,000 employees, NTL, which also contract manufactures CFLs for Indian lighting brands, now aims to strike out on its own in the emerging LED business.