Telecom operator Bharti Airtel has pulled the plug on its 3G services in Calcutta. The move is part of the company’s efforts to replace third generation mobile technology with 4G.

Airtel on Friday said it had re-farmed the 900-MHz band spectrum being used for 3G to strengthen its 4G network. The company will deploy L900 technology in the 900 MHz band to complement its 4G services in 2300 MHz and 1800 MHz bands.

“This is in line with our stated strategy of focusing on serving quality customers with best-in-class service experience. Going forward, we plan to re-farm all of our 3G spectrum across India and deploy it for 4G in a phased manner,” said Randeep Sekhon, CTO – Bharti Airtel, in a statement.

The company estimates that less than 10 per cent of its subscribers are on the 3G platform. These customers who are yet to upgrade their handsets or SIM cards will continue to have voice services, the company said. Airtel will continue to provide 2G services in Calcutta.

The company said it had notified its 3G customers, requesting them to upgrade their handsets and SIMs.

“All customers on 3G were duly notified and requested to upgrade their handsets/SIMs to continue enjoying best-in-class smartphone experience. 3G customers who are yet to upgrade their handsets/SIMs will continue to have access to high-quality voice services,” the company said.

Airtel had informed analysts in its fourth quarter earnings conference of 2018-19 that it had started re-farming the 900 MHz spectrum, which was being used for 3G.

“We have liberalised spectrum in 10 circles of 900 Mhz band and I would say by March 2020 our efforts will be to re-farm in all those 10 circles almost all of the sites with L900,” Gopal Vittal, joint managing director and CEO – India and South Asia, had said in response to a query from analysts.

According to Trai data, Airtel’s total wireless subscriber base in Calcutta as of April 2019 was 60,59,090.