Microsoft has entered a major three‑year agreement with Bengaluru‑based climate‑tech startup Alt Carbon to purchase 36,920 metric tons of verified carbon‑removal credits. The credits will be delivered by 2029 through the company’s Darjeeling Revival Project in eastern India, marking one of the largest enhanced‑rock‑weathering (ERW) deals in Asia.
The partnership comes after more than a year of scientific reviews, due‑diligence checks, and contract negotiations. Microsoft also secured an option to buy additional volumes if Alt Carbon meets strict monitoring and verification milestones. The deal is significant because the global market for high‑quality, scientifically verified carbon‑removal credits remains extremely limited, even as corporate demand grows.
Alt Carbon, founded in 2023, specialises in enhanced rock weathering, a process that accelerates natural carbon‑capture reactions. The company sources basalt from the Rajmahal Traps in eastern India and spreads the crushed silicate rock across farmland in West Bengal. When basalt reacts with rainwater and atmospheric CO₂, it forms stable bicarbonates, locking away carbon for thousands of years.
The startup has already issued nearly 10,000 carbon‑removal credits and expects to issue another 15,000 by the end of the year. It operates across North Bengal with more than 80 partner organisations, including farmer networks and research institutions.
Microsoft’s decision to proceed with the deal also follows reports that it had paused parts of its carbon‑removal procurement programme — claims the company denied. Instead, the tech giant says it is expanding its portfolio of durable, verifiable carbon‑removal solutions as part of its 2030 climate commitments.
Alt Carbon co‑founder Sparsh Agarwal said Microsoft required additional monitoring, reporting and verification (MRV) measures beyond standard industry norms, reflecting the company’s push for scientific rigour in carbon‑removal procurement.
This agreement strengthens India’s position in the emerging carbon‑removal technology ecosystem, while giving Microsoft a scalable pathway to meet long‑term climate goals.