Microsoft Backs Indian Startup Alt Carbon in Carbon Removal Push

Microsoft has signed a major carbon-removal agreement with Indian startup Alt Carbon, highlighting India’s growing importance in the global carbon credit market. The deal marks Microsoft’s first enhanced rock weathering partnership in Asia and further strengthens the company’s position as one of the world’s largest buyers of carbon-removal credits.

The agreement will see Alt Carbon deliver nearly 37,000 metric tons of verified carbon dioxide removal credits over the next several years, supporting Microsoft’s long-term climate commitments.

Microsoft Signs Carbon Removal Deal in India

Under the three-year agreement, Bengaluru-based Alt Carbon will provide 36,920 metric tons of carbon dioxide removal credits by 2029 through its Darjeeling Revival Project in eastern India.

Microsoft also secured the option to purchase additional carbon credits if the startup successfully meets future delivery and verification milestones.

The announcement comes shortly after reports suggested Microsoft had slowed parts of its carbon-removal procurement efforts. The company denied those claims, reiterating its commitment to achieving its sustainability goals while continuing to refine its climate strategy.

How Alt Carbon Removes Carbon From the Atmosphere

Founded in 2023, Alt Carbon specializes in carbon-removal projects using a process known as enhanced rock weathering.

The technique involves spreading finely crushed basalt and other silicate rocks across farmland. When these minerals interact with rainwater and atmospheric carbon dioxide, they accelerate natural chemical reactions that lock carbon away in stable bicarbonates.

Alt Carbon sources basalt from the Rajmahal Traps region in eastern India and deploys the material across agricultural land in West Bengal.

According to co-founder and president Sparsh Agarwal, discussions with Microsoft began in early 2025 and continued for more than a year before the agreement was finalized.

The process included extensive scientific evaluations, due diligence reviews, and contract negotiations. Microsoft also requested additional monitoring, reporting, and verification measures beyond standard industry requirements.

Demand for Verified Carbon Credits Continues to Grow

The carbon-removal market has expanded rapidly as companies seek ways to offset emissions and meet climate targets.

Although hundreds of startups now claim to remove carbon dioxide from the atmosphere, only a small number have successfully delivered verified carbon-removal credits at commercial scale.

Agarwal noted that buyers are increasingly focused on proven projects with verified delivery records.

Alt Carbon has already issued nearly 10,000 carbon-removal credits, which the company says represents the largest issuance globally for enhanced rock weathering projects. The startup expects to issue another 15,000 credits before the end of the year.

Expanding Across Indian Farmland

The company currently operates two major projects in North Bengal.

One project is dedicated to Japanese shipping giant Mitsui OSK Lines, while Microsoft’s credits will come from a larger initiative spanning tea estates and rice-growing regions.

Today, Alt Carbon works with more than 35,000 farmers across approximately 80,000 acres of farmland.

Credits generated through the Microsoft agreement will be issued via Isometric, which developed the methodology used for enhanced rock weathering verification.

Emerging Markets Gain Ground in Carbon Removal

The deal also highlights the increasing role of developing economies in the carbon-removal sector.

According to Agarwal, suppliers from the Global South now account for approximately 26% of carbon-removal credit issuances, compared with just 2% in 2022.

He noted that international buyers were initially cautious about Indian carbon projects when Alt Carbon launched. However, stronger verification standards and growing issuance volumes have improved confidence in the country’s carbon-removal industry.

Microsoft previously signed another carbon-removal agreement in India with Varaha, purchasing more than 100,000 tons of carbon dioxide removal credits generated through biochar projects.

Strong Investor Support Fuels Expansion

Alt Carbon’s credits have already attracted buyers through procurement initiatives such as Frontier and NextGen.

The startup also secured $12 million in seed funding last year in a round led by tech investor Lachy Groom.

Looking ahead, Alt Carbon plans to expand its deployment footprint by roughly five times over the next four to five years. The company has also developed its own monitoring and verification infrastructure, including laboratories in Bengaluru and Darjeeling that analyze soil and water samples to measure carbon removal.

As demand for high-quality carbon credits continues to rise, the Microsoft-Alt Carbon agreement represents another significant milestone for India’s rapidly growing climate technology sector.

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