Microsoft taps Alt Carbon in sign of India’s growing role in carbon removal
Microsoft agreed to buy nearly 37,000 tons of carbon removal credits from Alt Carbon, its first enhanced rock weathering deal in Asia.
Intelligence analysis by GPT-5.4 Mini
Microsoft’s three-year deal with Bengaluru startup Alt Carbon gives the company a new customer for its enhanced rock weathering credits and signals more confidence in India’s carbon-removal market. The agreement also shows how buyers are pushing for stricter verification as the market for proven supply stays tight.
Microsoft is paying an Indian startup to help pull carbon out of the air by spreading special rocks on farm fields, like using a sponge to soak up bad stuff. The big deal matters because the company wants proof that the carbon really stays locked away.
Analysis
The deal
Microsoft signed a three-year agreement to buy 36,920 metric tons of carbon dioxide removal credits from Alt Carbon, sourced from the startup’s Darjeeling Revival Project in eastern India. The company also has the option to buy more if Alt Carbon hits delivery and verification milestones.
Why this matters for Alt Carbon
This is Microsoft’s first enhanced rock weathering deal in Asia and a major validation for Alt Carbon, a Bengaluru startup founded in 2023. The company uses crushed basalt and other silicate rocks spread across farmland to trigger natural chemical reactions that help store carbon in stable forms. Alt Carbon says it sources basalt from the Rajmahal Traps and deploys it across farmland in West Bengal.
Verification is the real bottleneck
Alt Carbon co-founder and president Sparsh Agarwal said the talks began in early 2025 and took more than a year of scientific review, due diligence, and contract work. Microsoft asked for extra monitoring, reporting, and verification beyond registry rules, including more data sharing and carbon accounting protocols. That lines up with a broader problem in the market: there are many carbon-removal suppliers, but only a small number have delivered verified credits at commercial scale.
India’s role is growing
Alt Carbon says it has issued nearly 10,000 enhanced rock weathering credits so far, which it claims is the largest issuance of its kind. The startup expects another 15,000 credits by year-end and says it now works with more than 35,000 farmers across about 80,000 acres. It has also raised $12 million in seed funding led by Lachy Groom and built its own labs in Bengaluru and Darjeeling.
The article frames the deal as part of a broader shift: developers from the Global South now account for about 26% of carbon-removal credit issuances, up from roughly 2% in 2022. Microsoft’s earlier India deal with Varaha shows this is becoming a real procurement lane, not a one-off experiment.
Key points
- Microsoft agreed to buy 36,920 metric tons of carbon removal credits from Alt Carbon over three years.
- The deal is Microsoft’s first enhanced rock weathering agreement in Asia.
- Alt Carbon says the contract took more than a year of scientific review, due diligence, and negotiations.
- Microsoft required extra monitoring, reporting, and verification measures beyond registry standards.
- Alt Carbon says it now works with more than 35,000 farmers across about 80,000 acres in India.
If Alt Carbon keeps meeting Microsoft’s verification and delivery requirements, the deal could help it scale its project footprint and attract more buyers. The story also suggests Indian carbon-removal startups may gain credibility as international customers grow more comfortable with verified supply.
The deal depends on Alt Carbon meeting milestones and maintaining strict measurement standards, which can be hard and expensive to do at scale. The article also makes clear that verified supply is scarce, so growth could still be limited by the pace of delivery and the cost of proving each credit.
