Microsoft's First Enhanced Rock Weathering Deal in Asia
Microsoft has signed a three-year agreement to buy nearly 37,000 metric tons of carbon removal credits from Indian startup Alt Carbon, marking the tech giant's first enhanced rock weathering deal in Asia. This landmark transaction signals growing confidence in India's emerging climate technology sector and represents a significant milestone for carbon removal efforts in the Global South.
For more on how tech giants are driving climate innovation, see our coverage of carbon removal markets and the role of corporate procurement in scaling climate solutions.
The Darjeeling Revival Project: A Milestone for Carbon Removal
Under the agreement, Alt Carbon will deliver 36,920 metric tons of carbon dioxide removal credits by 2029 from its Darjeeling Revival Project in eastern India. The project leverages enhanced rock weathering—a proven carbon removal technique that accelerates natural geological processes to lock away atmospheric CO2.
Enhanced rock weathering is gaining traction as one of the most scalable carbon removal approaches. For technical details on how this method works and its environmental co-benefits, see our explainer on soil carbon sequestration techniques.
Alt Carbon: An Indian Climate Tech Startup Emerges
Alt Carbon is a Bengaluru-based startup founded in 2023 that focuses on carbon removal projects, with enhanced rock weathering as its flagship technique. The company sources basalt—a fine-grained volcanic rock—from the Rajmahal Traps in eastern India and deploys it across farmland in West Bengal.
The process works through natural chemical reactions: when crushed basalt mixes with rainwater and atmospheric carbon dioxide, it forms stable bicarbonates that remain locked in the soil. This not only removes CO2 from the atmosphere but also improves soil health and agricultural yields—a powerful co-benefit for Indian farmers. This aligns with broader trends in climate-smart agriculture.
Sparsh Agarwal, Alt Carbon's co-founder and president, told TechCrunch that discussions with Microsoft began in early 2025 and culminated after extensive scientific review, due diligence, and contract negotiations.
Microsoft's Continued Commitment to Carbon Removal
The agreement follows reports that suggested Microsoft—the world's largest buyer of carbon-removal credits—had paused parts of its carbon-removal procurement program. Microsoft explicitly rejected those claims, stating it remained committed to its climate goals even as it refined its sustainability strategy.
This deal demonstrates that Microsoft's commitment to carbon removal remains strong. The company continues to be the dominant force in the voluntary carbon market, and its procurement decisions carry significant weight across the industry. Microsoft's leadership in corporate climate action sets a precedent for other tech giants navigating decarbonization.
The Global Carbon Removal Market: From Promise to Practice
The deal comes at a critical juncture for the carbon removal market. Buyers increasingly seek proven carbon-removal projects as verified supply remains scarce. Hundreds of startups have emerged promising various carbon removal technologies, but only a small fraction have delivered verified credits at commercial scale.
Enhanced rock weathering represents one of the more scalable carbon removal approaches, but it requires careful implementation to ensure effectiveness and avoid unintended environmental consequences. Alt Carbon's project in West Bengal serves as a crucial case study for how this technology can work in diverse geographical contexts, contributing to the growing body of knowledge on carbon removal scalability.
Looking Forward: What This Deal Means for India and Beyond
Alt Carbon's partnership with Microsoft is more than a business deal—it's a validation of India's growing capabilities in climate technology. The company has navigated complex scientific, financial, and regulatory hurdles to deliver what Microsoft requires, setting a precedent for future Indian climate startups.
The success of this project could catalyze additional investment in India's climate tech sector, attracting both domestic and international capital. As global climate finance shifts toward emerging markets, projects like Alt Carbon's demonstrate that carbon removal can be both environmentally effective and economically beneficial for local communities.