India’s largest mobile operator Bharti Airtel has moved to match 4G upstart Reliance Jio’s data offering and given its prepaid customers free data for 90 days.

Airtel, with a 25 per cent market share, matched Jio’s INR50 ($0.70) per gigabyte offer with a special prepaid data package, according to the Economic Times. But its 90-day free offer only covers data, not voice and SMS.

After numerous delays and extensive testing, Jio launched commercial 4G service across the country’s 22 regions on 5 September. It is offering voice, SMS and 4G data service for free as part of a trial until the end of the year. Jio’s cheapest data offer, averaging just over INR50 ($0.70) per gigabyte from January, will be the lowest in the world, according to Mukesh Ambani, chairman of Reliance Industries.

India’s leading operators have sharply criticised Jio’s free voice offer, with Ambani on record as saying its customers will never pay for voice. The Cellular Operators Association of India (COAI) said its members are not obliged or in a position to provide sufficient interconnection points to help Jio as they don’t have the capacity or financial resources to handle a pending surge in voice traffic.

COAI and Jio have been involved in a war of words over interconnect access, with each pointing the finger at the other. In early August, Jio accused the country’s incumbent operators of deliberately sabotaging its entry by not providing it with adequate points of interconnection. COAI kicked off the row when it claimed the operator was offering a full-blown mobile service disguised as a trial.

The country’s other two major mobile players, Vodafone India (with a 19 per cent share) and Idea Cellular (17 per cent) have not yet responded to Jio’s deep price cuts. The second and third largest operators hold 4G spectrum in only about half the service regions that they operate in – Jio and Airtel both have 4G spectrum nationwide.

Ambani has expressed confidence that Jio will generate healthy returns, despite its low-cost model.

Fitch Ratings predicts that Jio’s entry into the telecoms market will be credit negative for the incumbents – especially smaller telcos – and should hasten industry consolidation. It expects the industry blended tariff to fall by 10-15 per cent in the next year.