Alt Carbon, an Indian climate-tech startup, has secured $12 million in seed funding to scale its innovative carbon dioxide removal technology across the country. The round was led by Lachy Groom, co-founder of robotics AI company Physical Intelligence.
The startup, founded by siblings Shrey and Sparsh Agarwal, emerged out of a personal crisis when their family’s tea estate in Darjeeling faced bankruptcy. Returning home in May 2020 anticipating the closure of Salem Hill estate, the Agarwals instead began exploring how carbon markets might rescue not only their own farm but also the local tea economy as a whole. After extensive research into available options, they discovered the potential of enhanced rock weathering—a method capable of locking away carbon dioxide for thousands of years—in transforming the region from climate vulnerability to climate innovation.
Initially piloted around their family property in Darjeeling on approximately 500 acres, the method now targets broader agricultural settings, including rice and bamboo farms throughout North Bengal. Alt Carbon’s ambitious goal is to remove 5 million metric tons of carbon dioxide from the atmosphere by 2030, eventually covering an extensive 500,000 hectares.
The startup employs enhanced rock weathering involving basalt rock dust, a waste product obtained from mines in India’s volcanic Rajmahal Traps region. Once spread on farmland, this basalt dust naturally reacts with rainwater and atmospheric carbon dioxide to form stable bicarbonate ions. These ions eventually make their way to oceans via rivers, where they deposit as calcium carbonate, sequestering carbon for over 10,000 years. Importantly, Alt Carbon’s approach uses readily available materials transported through existing freight networks, minimizing logistical emissions. The addition of their proprietary organic blend, named “Hari Maati,” further improves farmers’ soil health, crop yield, and sustainability.
Pricing per carbon credit for Alt Carbon currently stands around $270 per metric ton—much lower than direct-air capture methods, typically costing around $800 per ton. The team anticipates further lowering costs within the next few years.
To accurately quantify its carbon removal efforts, Alt Carbon deploys a robust, multi-layered monitoring system, combining direct soil and groundwater measurements, river monitoring, reactive transport modeling, and machine learning-driven analytics. These stringent verification methods are closely aligned with established standards from institutions like Isometric, Puro.earth, SBTi, ICVCM, and CORSIA.
With a dedicated team of 25 professionals, including several PhDs, split between laboratories in Darjeeling and Bengaluru, Alt Carbon plans to expand its analytical capabilities and establish a hardware studio to boost data collection processes. Leveraging advanced sensors and remote-sensing technology, the company aims for comprehensive and cost-effective tracking and reporting of impacts.
Recently, Alt Carbon signed key strategic partnerships, including a significant $500,000 pre-purchase agreement with Frontier, backed by an advanced market commitment involving Stripe, Alphabet, Shopify, Meta, and McKinsey. Additionally, they have secured an offtake agreement with Japanese shipping giant MOL Group for the purchase of 10,000 tons of carbon removal credits. Alt Carbon expects to deliver its first carbon credits within the coming month through the Isometric registry.
