Microsoft has entered into a groundbreaking three-year agreement with Indian startup Alt Carbon, committing to acquire approximately 37,000 tons of carbon removal credits. This collaboration marks the tech giant's inaugural enhanced rock weathering initiative in Asia.
As part of the deal, Alt Carbon will supply 36,920 metric tons of carbon dioxide removal credits by 2029, sourced from its innovative Darjeeling Revival Project located in eastern India. Furthermore, Microsoft retains the option to purchase additional credits contingent upon the startup achieving specified delivery and verification benchmarks.
This agreement follows recent discussions indicating that Microsoft, the largest global buyer of carbon-removal credits, had momentarily paused certain aspects of its carbon procurement strategy. However, the company has firmly stated its ongoing commitment to climate objectives while refining its sustainability approach.
Founded in 2023, Alt Carbon is a Bengaluru-based startup dedicated to carbon removal projects, particularly through enhanced rock weathering. This method involves distributing crushed basalt and other silicate rocks across agricultural land to accelerate natural chemical processes that sequester carbon dioxide. Alt Carbon sources basalt from the Rajmahal Traps and applies it in West Bengal, where it reacts with rainwater and atmospheric carbon to create stable bicarbonates.
Negotiations with Microsoft began in early 2025 and culminated over a year later, following rigorous scientific evaluations and contract discussions. Alt Carbon's co-founder, Sparsh Agarwal, noted that Microsoft mandated additional monitoring, reporting, and verification (MRV) measures beyond standard registry requirements to ensure robust data-sharing and carbon quantification protocols.
The partnership highlights a growing demand for verified carbon-removal projects, as the market currently faces a shortage of confirmed supply. While numerous startups claim to offer carbon removal solutions, only a select few have successfully delivered verified credits on a commercial scale.
"Currently, the challenge lies in the abundance of suppliers, yet a scarcity of verified deliveries," Agarwal explained. "When credible companies emerge, there is a collective desire to secure a share of the available supply."
Alt Carbon has already issued nearly 10,000 carbon-removal credits through enhanced rock weathering, making it a leader in this sector. The startup anticipates issuing an additional 15,000 credits by year-end and has expanded its operations to include rice-growing regions, collaborating with over 35,000 farmers across approximately 80,000 acres.
Credits generated under the Microsoft agreement will be managed through Isometric, a registry that has pioneered enhanced rock weathering methodologies. This collaboration also underscores the increasing significance of emerging-market suppliers in the carbon removal landscape, with developers from the Global South now responsible for about 26% of carbon-removal credit issuances.
As demand for verified carbon-removal credits rises, Alt Carbon plans to broaden its operational footprint fivefold over the next four to five years. The startup, which raised $12 million in seed funding last year, has established its own MRV infrastructure to enhance verification capabilities and reduce measurement costs, critical for scaling carbon removal initiatives both in India and globally.
