Alt Carbon Signs Multi-Year Deal with Microsoft to Remove 36,920 Tonnes of CO2 Through Enhanced Rock Weathering in India

Alt Carbon, a Bangalore-based deeptech startup, has announced a multi-year agreement with Microsoft to remove up to 36,920 metric tonnes of carbon dioxide through Enhanced Rock Weathering, marking Microsoft's first carbon removal deal in Asia and the largest ERW commitment yet made in the Global South. The verified carbon dioxide removal credits will be generated through the Darjeeling Revival Project, an initiative to revive Darjeeling's heritage tea estates and neighbouring agricultural networks including rice paddies across more than 80,000 acres of agricultural land in West Bengal, working with more than 35,000 farmers across 60 gram panchayats and creating over 250 green jobs. Alt Carbon has issued 9,566 carbon credits to date through the Isometric registry and the Microsoft deal provides the opportunity for additional volume purchases subject to successful delivery and verification milestones.

 

The Enhanced Rock Weathering Technology and Its Carbon Permanence

 

Enhanced Rock Weathering involves sourcing waste basalt rock and spreading it across agricultural farmlands, where the basalt reacts with carbon dioxide dissolved in rainwater and permanently stores the carbon as stable bicarbonate ions. Over time these ions travel through river networks to the ocean where they eventually reside as calcium carbonate in the form of corals and seashells for over 1,000 years, providing a storage permanence that significantly exceeds most nature-based carbon removal pathways. The Darjeeling Revival Project further adapts agriculture to climate impact by boosting soil health, balancing pH and improving crop yields for farmers, creating a co-benefit structure that makes ERW deployment commercially attractive to farming communities and supports sustained farmer participation across the programme.

Shrey Agarwal, Chief Executive Officer and Co-founder of Alt Carbon, said the deal with Microsoft is built upon years of work building high-integrity carbon removal infrastructure in India across laboratory capabilities, field operations and farmer networks, and that Alt Carbon has measured and indexed thousands of soil and water samples across land parcels covering an area roughly twice the size of Manhattan. He described climate change as one of the most significant civilizational challenges and said India can be a global leader in technology-based carbon removal. Phil Goodman, Program Director for Carbon Removal at Microsoft, said the contract uses field deployments to collect primary and secondary quantification methods for carbon quantification under a high standard to safeguard against environmental impacts, and expressed encouragement at Alt's efforts to build durable carbon removal capacity in India given their past delivery success.

 

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The Measurement, Reporting and Verification Infrastructure

 

Alt Carbon has built a proprietary MRV infrastructure to support the rigorous verification standards that institutional buyers like Microsoft require, operating two laboratory facilities including Shonku Labs at the Indian Institute of Science campus in Bangalore for core research and development and the Darjeeling Climate Action Laboratory at Kamala Tea Estate for field sample processing. The D-CAL facility is scaling to process up to 100,000 samples annually by 2026, with more than 20,000 samples already analysed and processed to date, providing the analytical throughput needed to verify carbon fluxes, soil chemistry changes and environmental safeguards across the large agricultural footprint. By expanding laboratory throughput and field measurement capacity, Alt Carbon aims to reduce the cost of MRV over time, directly addressing one of the principal barriers to scaling high-integrity enhanced rock weathering.

In addition to delivering verified credits to Microsoft, Alt Carbon will expand field trials, conduct deep soil and porewater monitoring, collect crop uptake measurements and commit to public data-sharing to advance the scientific understanding of ERW in tropical agricultural systems. This research commitment extends the value of the Microsoft deal beyond the immediate credit transaction into a contribution to the global knowledge base on ERW scalability in the Global South, where geological, climatic and agricultural conditions differ significantly from the temperate environments in which most ERW research has been conducted. Sparsh Agarwal, President and Co-founder of Alt Carbon, said ERW is emerging as a scalable and rigorous pathway for carbon removal technologies globally with the potential to remove up to 2 gigatons of carbon dioxide annually across the Global South.

 

The Global South's Growing Role in Carbon Removal

 

The Alt Carbon and Microsoft transaction sits within a broader structural shift in the engineered carbon removal market, with Global South suppliers now accounting for 26 percent of carbon dioxide removal issuances, up from under 2 percent in 2022. Sparsh Agarwal said the efficiency gap is striking, with Global South suppliers producing 15 times as many engineered carbon removal credits per dollar of funding as their counterparts in the Global North, driven by the combination of favourable geologies, lower operational costs and a new generation of science-first developers. This efficiency advantage positions India and other Global South markets as critical supply regions for the growing corporate demand for verified, high-integrity carbon removal at commercially viable prices.

The combination of India's geological basalt resources, large agricultural land base, established farming communities and rapidly developing scientific infrastructure creates a distinctive competitive advantage for ERW deployment at scale that Alt Carbon is positioned to exploit. Microsoft's decision to make its first Asian carbon removal purchase through ERW rather than more established nature-based pathways reflects growing institutional confidence in ERW's permanence credentials and the quality of verification methodologies being applied by leading developers. The deal also validates Alt Carbon's investment in laboratory infrastructure and MRV capability as the foundation for attracting the most demanding corporate buyers to Indian carbon removal projects.

 

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Outlook for Alt Carbon and Indian Enhanced Rock Weathering

 

Alt Carbon's mission to remove 5 million metric tonnes of carbon dioxide by 2030 will require substantial scaling of its current operations across both its ERW programme in Darjeeling and the newly launched Bengal Renaissance Project, an industrial biochar programme building a network of biomass banks and pyrolysis and gasification plants across Eastern India. The Microsoft deal provides commercial validation and financial resources to support this scaling ambition, while the additional volume option subject to delivery milestones creates a performance-linked growth pathway that aligns the interests of both parties around verified outcomes rather than volume commitments. Whether Alt Carbon can achieve the laboratory throughput, field monitoring coverage and farmer network expansion needed to deliver at the scale its mission requires will be the critical operational test of the next phase of the company's development.

Sustained delivery at the scale implied by the 5 million tonne target would establish India as a leading global hub for technology-based carbon removal and demonstrate that the combination of scientific rigour, community engagement and cost-efficient operations available in the Global South can produce carbon removal credits that meet the highest international quality standards. The convergence of growing corporate demand for permanent, high-integrity carbon removal, India's natural resource advantages for ERW deployment and Alt Carbon's accumulated MRV infrastructure creates conditions in which the company is well positioned to become one of the defining carbon removal platforms of the current decade.

 

Source: Alt Carbon