Microsoft has deepened its commitment to climate action through a new agreement with Alt Carbon, an Indian startup pioneering carbon removal technologies. This deal follows over a year of rigorous scientific review and extensive due diligence, highlighting a shift in the carbon removal market toward verified, evidence-based methods rather than speculative claims.
The project harnesses enhanced rock weathering, a natural process involving spreading finely ground basalt rock sourced from the Rajmahal Traps across agricultural lands in West Bengal. According to Alt Carbon, the basalt interacts with rainwater and atmospheric carbon dioxide to form stable bicarbonates, effectively locking carbon away while enhancing soil health and productivity on local farms. This approach aims to build a durable carbon removal model centered on permanence instead of short-lived offsets, an ambition grounded in scientific monitoring.
Alt Carbon launched its Darjeeling Climate Action Lab to develop and scale this model, expanding its footprint in India’s carbon removal sector. By May 2026, the startup had issued verified credits representing nearly 10,000 tonnes of carbon dioxide removed—marking the world’s largest recorded issuance from enhanced rock weathering by volume. Early buyers included key climate coalition members such as Stripe, Google, Shopify, and Match Group, signaling strong market confidence. The Darjeeling Revival project also attracted international buyers like Mitsui O.S.K. Lines, which obtained thousands of tonnes of removal credits.
Alt Carbon’s rapid growth was fueled by a substantial seed funding round raised in May 2025, which stood as India’s largest climate tech seed financing at that time. This capital, combined with early sales, transformed a regional pilot into a project now regarded as a benchmark for reliable carbon removal in Asia.
Microsoft’s pact with Alt Carbon complements its earlier agreement to purchase 1.5 million tonnes of verified removal credits from a separate Indian effort, the Panna afforestation project. That agreement, spanning 30 years, also underwent years of testing and validation, underscoring the company’s methodical approach to climate investments.
Together, these partnerships indicate India’s evolution from a peripheral player into a central arena for credible, long-duration carbon removal projects—a shift crucial for global climate strategies targeting net-zero emissions.