Bharti Airtel, India’s largest cello by subscribers, has launched 4G services on mobiles in the cities of Chandigarh, Mohali and Panchkula in the Punjab circle, the Economic Times reports. Airtel previously offered data-only Time Division Long Term Evolution (TD-LTE) services in those cities, but has now made its 4G service available on handsets. Airtel has implemented circuit switched fall back (CSFB) technology, allowing customers to use the 4G network for data services, whilst calls will be routed through Airtel’s 2G network.