Bharti Airtel, India’s second-largest mobile carrier by number of users, posted its seventh straight quarterly profit rise on Thursday, as subscribers upgraded to higher-margin telecom plans amid a steady rise in the customer base.

Airtel’s industry-leading average revenue per user (ARPU) — a key metric of profitability — rose 5.7 percent year-on-year to Rs. 259 during the quarter, with the share of users on faster 4G and 5G connections surging to 79 percent, a Reuters report stated yesterday.

Indian telecom operators have been focused on boosting revenue by encouraging users to move to higher-value plans. Both Airtel and rival Reliance Jio have scrapped their entry-level 4G and 5G packs to encourage migration to pricier options.

India’s telecom sector has witnessed intense competition since Jio’s entry in 2017 with the Reliance group company overtaking peers to command the largest user base.

Airtel’s India user base rose 12.6 percent year-on-year to 465.9 million as of December 31, below Jio’s 515.3 million. The firm’s consolidated pre-tax profit rose 34.4 percent to Rs. 125.58 billion ($1.39 billion) for the quarter ended December 31, from 93.46 billion rupees a year earlier.

The results include a Rs. 2.57 billion charge linked to the implementation of new labour codes. The firm’s year-ago profit had got a Rs. 75.5 billion boost from a higher valuation of its stake in telecom infrastructure provider Indus Towers.

Airtel’s “balance sheet strength, reinforced by strong cash generation and sustained deleveraging” positions it well to invest in new growth opportunities, Executive Vice Chairman Gopal Vittal said in a press release.

The firm’s overall revenue climbed 19.6 percent to Rs. 539.82 billion, including proceeds from Indus Towers, in which Airtel bought a majority stake last year.

Last month, Jio reported a 11 percent rise in quarterly profit, while smaller rival Vodafone Idea’s losses narrowed.