Bharti Airtel, the world's fifth-biggest mobile phone carrier by subscribers, reported a 22 percent fall in quarterly profit — its eighth straight quarter of declining profits — hit by higher interest costs and losses on currency fluctuations.

An Indian man checks a new mobile phone at a shop in New Delhi on May 12, 2010.

The sector's profitability has been squeezed after the entry of the new operators triggered a vicious call-price war. Market leader Bharti and some of its rivals raised call prices in the middle of last year, which was the first such increase in at least two years.