Idea Cellular, India’s third largest mobile operator, followed the market leader in defending itself from generous free offers by 4G newcomer Reliance Jio by introducing its own special offer giving 4G customers additional free data each month.

The move comes a week after the country’s largest mobile operator Bharti Airtel offered customers who upgrade to a new 4G handset 3GB of free data a month for 12 months.

Idea’s offer is nearly the same as Airtel’s, giving prepaid 4G users 3GB of additional data as well as unlimited calls and SMS each month for 12 months, the Economic Times reported. A similar offer is available for new and existing post-paid customers.

Idea and Airtel are responding to Jio’s latest free data plans. In early December, it extended its free voice, data and video offer from the end of 2016 to the end of March as part of a new year offer. The upstart claimed to have 65 million subscribers.

Second-ranked Vodafone India last month offered to double customers’ 4G data allotments, which effectively reduces data prices by 50 per cent.

Despite Jio’s free offer, the top three players have continued to add subscribers. Airtel added nearly 12 million users in the second half of 2016, Vodafone picked up 6.3 million and Idea added 9 million, according to GSMA Intelligence.