* TO SELL APPLE WATCH SERIES 3 Source text:[Bharti Airtel, India's largest telecommunications service provider today announced that it will begin selling Apple Watch Series 3 (GPS + Cellular), which adds built-in cellular to the world's number one watch, with pre-registrations starting May 4, 2018 and availability on May 11th, 2018. Customers can pre-register on Airtel website.] Further company coverage: