mumbai/bengaluru, Sept. 3 -- Some of India's biggest data-centre operators are enjoying a rare combination: faster revenue growth and fatter margins. But the boom in their earnings for fiscal year 2026 (FY26) is being driven less by artificial intelligence (AI) than by existing capacity filling up. Bharti Airtel-owned Nxtra Data, AdaniConneX, Sify Infinit Spaces and IPO-bound ESDS Software Solutions reported strong revenue growth in FY26, according to a Mint review of company filings. All four reported their fastest revenue growth and strongest operating margins in at least three years. AdaniConneX and Nxtra also recorded their sharpest operating-margin expansion in at least three years. Together, the four account for more than a third of India's data-centre market, according to Anarock Capital, the investment and financial advisory arm of real estate services firm Anarock Group. Four others-CtrlS Datacentres, STT Global Data Centres India, NTT India and Yotta Data Services-also reported higher revenue growth in FY25, but have yet to disclose their FY26 earnings. The performance comes amid a broader expansion in India's data-centre industry, driven by rising cloud adoption, data localization and the growing computing demands of AI. Over the past year, domestic conglomerates, global technology companies including Google, Amazon, Microsoft and Meta, and standalone operators have committed more than $250 billion to new data centre capacity in India, according to a Mint analysis of investment announcements made. "FY26's high revenue and profitability come from capacity built in the last cycle reaching utilization, rather than from AI workloads," said Sanchit Vir Goghia, chief executive of technology advisory firm Greyhound Research. "AI is becoming an important source of incremental demand, but it is not yet the main driver of current revenues," said Kashyap Kompella, analyst and founder of technology consultancy firm RPA2AI Research. "Most current earnings continue to come from cloud, enterprise, BFSI, telecom, digital content and other conventional workloads." Nxtra's revenue jumped 17.1% year-on-year to Rs.2,434 crore in FY26, its fastest growth in three years, helped by capacity expansion. In March, it raised $1 billion from Alpha Wave Global, Carlyle and Anchorage Capital to expand further. Sify Infinit Spaces, an arm of Sify Technologies and the first to build a commercial data centre in India, reported a 23.2% revenue rise to Rs.1,760.5 crore, against 28.2% rise in FY25. The company attributed the growth to "continued demand from hyperscale clients, whose expanding digital infrastructure requirements are reshaping the sector." "With hyperscalers and small clients alike expanding rapidly, there is ample opportunity to capture customers, even though the market is competitive," chief executive Sharad Agarwal had told Mint on 11 August. AdaniConneX, the joint venture between Adani Enterprises and EQT-backed EdgeConneX, reported revenue of Rs.1,084 crore, its fastest growth in two years. It aims to develop 2GW of renewable-powered data-centre capacity by 2030 to "meet the surging demand for Data Center infrastructure and solutions," according to its FY26 annual report....