Indian mobile telecoms firms added 9.2 million users in July, taking subscribers in the world’s fastest growing wireless market to nearly 300 million, the Telecom Regulatory Authority of India said on Monday. Leading mobile firm Bharti Airtel signed up 2.7 million customers, enough for it to overtake state-run Bharat Sanchar Nigam Ltd as India’s largest telecom firm by total subscribers, including fixed-line subscribers. Second-ranked mobile firm Reliance Communications added 1.