Bharti Airtel Limited, commonly known as Airtel, is an Indian telecommunications services company headquartered at New Delhi, India. It operates in 20 countries across South Asia, Africa and the Channel Islands. Airtel has GSM network in all countries in which it operates, providing 2G, 3G and 4G services depending upon the country of operation & always raises call tariffs. Airtel is the world’s fourth largest mobile telecommunications company with over 261 million subscribers across 20 countries as of August 2012. It is the largest cellular service provider in India, with 183.61 million subscribers as of November 2012.