Bharti Airtel, India’s biggest mobile operator, posted an enormous 89.1 per cent year-on-year increase in consolidated Q4 net income, to INR9.62 billion ($158.9 million), helped by continued strong growth in its domestic market and improved operational efficiencies.

Group sales were up 13.5 per cent, to INR222.2 billion.

The top-line was boosted by 3G and mobile data growth in its home market. The number of 3G data subscribers increased by 16 per cent, to nearly 11 million, compared with three months previously (and up 72 per cent compared with the end of March last year).

Moreover, the total number of Airtel’s mobile data subscribers grew by 7 per cent in India, to 58.1 million, in the first three months this year. That represents around 28 per cent of the operator’s total domestic mobile subscriber base, up from 23.1 per cent 12 months previously.

Weakening competition in India, as smaller rivals have fallen by the wayside, also helped Airtel lower churn and bump up voice call prices. Voice ARPU was up 2 per cent, year-on-year, to INR162. Although a small percentage rise, it’s significant given voice still represents over 80 per cent of Airtel’s mobile service revenues in India.

Pooling together voice and data growth, Airtel managed to notch up a 9.7 per cent year-on-year increase in mobile services revenue, to INR120.8 billion, during Q4. Mobile data accounted for 11.1 per cent of total mobile revenue in India during the quarter compared with 6.5 per cent during Q4 2013.

Group mobile data revenues increased by 93.4 per cent, over the same period, to INR19 billion.

Increase in EBITDA margin, an indicator of operational efficiency, was also impressive. In relation to Airtel’s mobile business in India, the EBITDA margin widened from 30.6 per cent (Q4 2013) to 34.9 per cent. Airtel attributed the margin improvement to a combination of revenue growth and “enhanced opex productivity”.

At a group level,  EBITDA margin increased from 30.9 per cent to 32.9 per cent.

Africa, however, continues to weigh heavily on consolidated results. Comprising 17 countries across the continent, Airtel’s business in Africa drummed up a modest 2 per cent year-on-year increase in Q4 revenue, to $1.15 billion, and it’s still not profitable.

Airtel’s international business, the bulk of which is accounted for by Africa – along with operations in Bangladesh and Sri Lanka – reported a net loss (before exceptional items) of INR12.2 billion. That’s more than double the loss reported in Q4 2013.

Consolidated full-year net income was INR27.7 billion, a 21.8 per cent increase over the previous year. Group turnover was INR857.5 billion, up 11.5 per cent.