Startup Deep Dive : GreenJams — the carbon-negative brick that beat a rival made of hemp

In April 2023, contractors finished a 1.8-kilometre perimeter wall on ITC’s newly acquired land in Kapurthala, Punjab, built from 28,000 blocks made of burnt paddy straw, fly ash and steel-industry waste — a wall whose maker says it locked away more carbon than went into producing it, a claim backed by an independently audited Environmental Product Declaration (International EPD System registration EPD-IES-0006876, published October 2022). The contradiction: the ten-person Visakhapatnam company that made those blocks, GreenJams, closed its most recent full financial year with revenue of roughly ₹1 crore, even as it says its live order pipeline runs to about ₹170 crore.

That gap between a marquee industrial client and a still-tiny balance sheet is the story of GreenJams. It makes Agrocrete, a load-bearing building block manufactured from crop residue that would otherwise be burned in fields, and it has spent seven years discovering that the hardest part of “carbon-negative construction” was never the chemistry — it was finding a waste stream cheap and abundant enough to build a business on.

Quick facts

What they do

GreenJams designs and manufactures Agrocrete, a carbon-negative building block made by combining crop residue such as paddy straw with a low-carbon mineral binder derived from steel, paper and power-industry by-products, then hydraulically pressing and curing it into solid or hollow blocks that replace conventional bricks in walling. It sells to institutional and industrial builders, contractors and, increasingly, sustainability-conscious developers, positioning Agrocrete not as a niche eco-material but as a like-for-like substitute for the brick and concrete-block category — one the company says cuts construction cost by up to 50% and raises thermal insulation roughly 3.5 times over conventional blocks. Manufacturing runs out of bases in Visakhapatnam and Goa, with the company describing a 15-node partner-manufacturing network and more than 50 clients served to date.

The origin

Tarun Jami trained as a civil engineer at IIT Roorkee, and it was there, around 2013, that he first encountered hempcrete — a hemp-and-lime building material prized for being carbon-negative and thermally efficient. He kept pulling on that thread through a postgraduate degree in environmental science, completed in 2016, and doctoral-track research in hemp concrete affiliated with CSIR’s Central Building Research Institute in Roorkee. In July 2017 he formalised the work as GreenJams Infrastructures LLP, bringing in his father, who left a position at Tata Projects, and his brother Varun, a lawyer by training, to run operations, partnerships and legal matters while Tarun focused on the material science.

The founding insight was simple and, at the time, narrow: India’s construction industry needed a building material that sequestered carbon instead of emitting it, and hemp-based concrete looked like the answer. What the founders had not yet worked out was where that hemp-like feedstock would come from at a price and volume that made sense for construction, rather than for niche green-building showcases.

The struggle years

The early years were spent proving the science and hitting a wall on economics. Tarun’s first attempts at pure lime-and-cement bricks failed outright. Once the team had a working hemp-based block, branded Hempbloc — combining hemp stalks with GreenJams’ own binder, BINDR, into a non-load-bearing panel — it ran into a structural problem that no amount of chemistry could fix: industrial hemp cultivation in India is thinly spread and tightly licensed, so sourcing hemp stalk at scale left Hempbloc roughly three to five times more expensive than conventional walling material. A carbon-negative product that cost multiples of a fired clay brick was never going to displace fired clay bricks.

For several years, then, GreenJams had a scientifically credible material with no viable route to a mass market — a well-read civil engineer’s thesis in block form, propped up by family capital and no outside financing to speak of.

The turning point

The pivot came from an unrelated trip. In late 2019, Tarun was in Delhi during one of the city’s worst smog episodes and, digging into why, learned how much of the region’s particulate pollution traced back to farmers burning paddy stubble after harvest — a practice estimated at the time to be responsible for a large share of the city’s poor air quality, by his own account. The realisation reframed the entire business: instead of chasing a purpose-grown, license-constrained input like hemp, GreenJams could build on a waste stream that already existed in enormous, geographically concentrated, essentially free volumes — the crop residue farmers were setting alight because they had no other use for it. That pivot produced Agrocrete, and the company re-incorporated as GreenJams BuildTech Private Limited on 31 October 2019 to reflect the shift.

The numbers either side of that pivot are stark. Before it, GreenJams had a product line, Hempbloc, that cost three to five times more than what it was meant to replace. After it, the company built its first carbon-negative structure — a 1,100 square foot, steel-free industrial workshop in Roorkee, completed on 18 February 2021 in four days, which captured 3.1 tonnes of CO2 and has since survived two earthquakes and three cyclones. Eighteen months later, on 21 October 2022, GreenJams became the first Indian construction-materials startup to publish a third-party-verified Environmental Product Declaration proving a cradle-to-gate carbon footprint of minus 0.14 kilograms of CO2 per kilogram of Agrocrete produced. Six months after that, on 28 April 2023, ITC — through contractor Tricon Buildwell — completed its 28,000-block, 1.8-kilometre perimeter wall at Kapurthala, which GreenJams says captured 38.5 tonnes of CO2 and avoided a further 144 tonnes of emissions, with Tricon reporting construction 2.5 times faster than with conventional block. A research pivot triggered by a smog-filled meeting in Delhi had, within three and a half years, produced an independently verified material and an enterprise-scale order from one of India’s largest conglomerates.

The money behind it

• Seed round, 14 October 2021: $734,811 — GreenJams’ first institutional seed capital, raised roughly eight months after its first carbon-negative structure went up in Roorkee (Tracxn).
• Angel round, 7 September 2022: $195,673 — a bridge round from 33 angel investors, coming weeks before the company’s EPD was formally published (Tracxn).
• Swachhata Startup Challenge grant, September 2022: ₹25 lakh (reported as roughly €30,000) — a non-dilutive grant from the Ministry of Housing and Urban Affairs and the Agence Française de Développement, which named GreenJams a national winner for tackling construction-sector carbon and waste; the win also brought follow-on incubation support from Villgro and up to $100,000 in AWS promotional cloud credits (GreenJams; Business Standard).
• Seed round, 4 June 2025: $878,542 — led by Fondation Botnar, a Swiss philanthropic foundation focused on child and youth wellbeing in fast-urbanising cities, with the round drawing roughly five investors; post-money valuation was not disclosed (Tracxn).

Across three disclosed priced rounds, GreenJams’ round-by-round figures on Tracxn add up to roughly $1.8 million raised, though the same profile’s own aggregate summary states total funding of $1.12 million from 40 investors over three rounds — a discrepancy Tracxn’s data does not reconcile, so both figures are reported here rather than one being silently chosen. What is consistent across sources is the shape of the capital stack: two priced seed-stage rounds bookending a government grant and incubation support, rather than a conventional venture-only trajectory. Fondation Botnar, the largest single disclosed backer, is a foundation rather than a commercial venture fund, which changed the kind of capital available to GreenJams (patient, mission-aligned) more than it added typical growth-equity firepower.

How it makes money

• Agrocrete — solid and hollow load-bearing blocks made from paddy straw, fly ash and BINDR binder, with a verified cradle-to-gate global warming potential of −0.14 kgCO2e/kg; sold as a direct substitute for fired clay bricks and conventional concrete blocks (GreenJams; International EPD System).
• Novastone — zero-cement blocks, bricks and pavers with a reported GWP of 0.03 kgCO2e/kg, aimed at hardscaping and paving rather than structural walls (GreenJams).
• BINDR — an alkali-activated replacement for ordinary Portland cement in mortar and plaster, which the company says reaches 53 MPa strength by day seven, versus the conventional 28-day benchmark for OPC, and cuts cement’s embodied carbon by roughly 80% in the applications it replaces (GreenJams; Construction World, June 2026 interview with Tarun Jami).
• Three manufacturing and go-to-market models, per the company: company-run on-site production units set up near a construction project; hyperlocal toll manufacturing, where local block-makers use GreenJams’ mix and press technology under a fee arrangement; and decentralised circular manufacturing sited close to agricultural-residue or demolition-waste sources (GreenJams).
• Where the margin is meant to sit: the company does not publish a take rate or per-block margin, but its own case studies emphasise installed-cost savings of up to 50% and construction-speed gains (2.5 times faster on the ITC wall) rather than a lower sticker price alone — the pitch is total project economics, not ex-factory block price.
• The part buyers get wrong: Agrocrete is marketed and used as a walling substitute for bricks and blocks, not as a replacement for higher-value structural elements like reinforced concrete or steel — so its addressable spend is the walling line item in a project budget, a smaller pool than “construction materials” broadly.

The numbers

All three years are drawn from GreenJams BuildTech’s MCA-linked financial filings as aggregated by Tofler and Tracxn. Absolute rupee profit or loss is not published in any source found for this piece; only growth-rate metrics (profit and EBITDA CAGR) are available, and they are reported here as such rather than converted into an invented rupee figure. Set against this, the company states an order pipeline of about ₹170 crore (~$17.7 million at $1 ≈ ₹96.0 as of 18 September 2026 — the company’s own materials round this to roughly $20 million, likely using a different exchange-rate snapshot). A roughly 170-times gap between quoted pipeline and the most recent booked annual revenue is the single most important number in this piece: it says GreenJams has moved from proving its material works to proving it can sell it, but has not yet closed that loop at scale.

Where the money comes from

• Geography: the company reports 15 completed projects across 7 Indian states, run out of two disclosed manufacturing bases in Visakhapatnam (Andhra Pradesh) and Goa (GreenJams).
• Enterprise/industrial: ITC’s 1.8-kilometre, 28,000-block perimeter wall at Kapurthala, Punjab, completed 28 April 2023 — GreenJams’ largest single verified order by block count (GreenJams case study).
• Owner-builder/industrial-small: a 1,100 square foot plastics-industry workshop in Roorkee, Uttarakhand, completed 18 February 2021 — the company’s first fully carbon-negative structure (GreenJams case study).
• Social/nonprofit: a roughly 1,300 square foot vocational-training and leprosy-clinic building using about 2,000 Agrocrete blocks, built with support from Habitat for Humanity’s Terwilliger Center for Innovation in Shelter (GreenJams).
• The surprise: the largest disclosed order did not come from a green-building developer chasing a sustainability certification — it came from a diversified conglomerate’s routine industrial land-development capex (a boundary wall), suggesting the near-term demand is less about eco-positioning and more about cost and speed on ordinary line items.

The risks

• Feedstock economics can flip fast. GreenJams already discontinued Hempbloc, an earlier carbon-negative product, once it became clear that India’s licensed, thinly spread industrial-hemp supply chain made it three to five times costlier than the material it was meant to replace (Construction World; company history). Agrocrete’s own input, paddy straw, is seasonal and geographically dispersed to harvest windows, which is exactly the kind of feedstock-supply variability that broke the previous product line.
• A wide pipeline-to-revenue gap. GreenJams states an order pipeline of roughly ₹170 crore against FY25 revenue of about ₹1 crore in its MCA filings (GreenJams; Tofler/Tracxn) — a roughly 170-times gap that is not unusual for an early-stage industrial-materials firm quoting a multi-year pipeline against one year of billed revenue, but it does mean the headline pipeline number says little about near-term cash generation until conversion is demonstrated.
• A capital stack light on commercial growth equity. Of GreenJams’ disclosed backers, the largest single round (June 2025) was led by Fondation Botnar, a philanthropic foundation, layered on top of a government-AFD grant (2022), Villgro incubation support and AWS cloud credits (Tracxn; GreenJams); no mainstream venture growth-equity fund appears among its named backers. Mission-aligned capital of this kind does not always scale at the pace a national manufacturing build-out would require.

The takeaway

The lesson in GreenJams’ seven years is not really about carbon chemistry — it is about feedstock economics. The company spent its first phase chasing a scientifically elegant, purpose-grown input, hemp, and found that being carbon-negative on paper meant nothing if the raw material was scarce and licensed. It only became a business people would actually buy from once it switched to an unglamorous, already-burning waste stream that was locally abundant and effectively free. For any venture built on being “sustainable,” the harder and more decisive question is rarely whether the science works; it is whether the input can be sourced at the volume and price the market it wants to serve can actually pay.

Frequently asked questions

What is Agrocrete made of?

Agrocrete is made from crop residue, primarily paddy straw, combined with a low-carbon mineral binder called BINDR that is derived from steel, paper and power-industry by-products, then hydraulically pressed and cured into solid or hollow building blocks (GreenJams).

Is GreenJams’ carbon-negative claim independently verified?

Yes. GreenJams published a third-party-verified Environmental Product Declaration on the International EPD System on 21 October 2022 (registration EPD-IES-0006876), showing a cradle-to-gate global warming potential of minus 0.14 kilograms of CO2 per kilogram of Agrocrete — meaning the process removes more carbon than it emits up to the factory gate.

Who founded GreenJams and when?

Tarun Jami, a civil engineer trained at IIT Roorkee, started the work as GreenJams Infrastructures LLP in 2017 with his father and brother Varun Jami; the current operating entity, GreenJams BuildTech Private Limited, was incorporated on 31 October 2019 in Visakhapatnam after the company pivoted from hemp-based materials to crop-residue-based Agrocrete.

How much funding has GreenJams raised?

GreenJams has raised money across three disclosed rounds — a $734,811 seed round in October 2021, a $195,673 angel round in September 2022, and a $878,542 seed round in June 2025 led by Fondation Botnar — plus a ₹25 lakh non-dilutive government grant in 2022. Tracxn’s round-level figures sum to roughly $1.8 million, though its own summary metric separately states $1.12 million; both figures are reported here because the source does not reconcile them.

Who are GreenJams’ customers?

Disclosed customers span an industrial conglomerate (ITC, for a 28,000-block perimeter wall in Kapurthala, Punjab), an industrial workshop owner in Roorkee, and a nonprofit vocational-training and clinic project built with Habitat for Humanity’s Terwilliger Center. The company says it has served more than 50 clients across 15 completed projects in 7 Indian states.

Sources

Figures are as of September 2026. Currency converted at $1 ≈ ₹96.0 as of 18 September 2026 (Trading Economics).

• GreenJams, official site and case studies — greenjams.org (accessed September 2026)
• GreenJams, “World’s First Verified Carbon-Negative Construction Block” — greenjams.org, October 2022
• GreenJams, “Vizag Start-up GreenJams wins Swachhata Startup Challenge 2022” — greenjams.org, September 2022
• GreenJams case study, “Industrial Building, Roorkee, Uttarakhand” — greenjams.org, February 2021
• GreenJams case study, “Perimeter Wall — 1.8 km, Kapurthala, Punjab” — greenjams.org, April 2023
• International EPD System, registration EPD-IES-0006876:002 — environdec.com, published 21 October 2022
• Tracxn, GreenJams company profile — tracxn.com, accessed September 2026
• Tofler / TheCompanyCheck, GreenJams Buildtech Private Limited financials (FY23–FY25) — tofler.in and thecompanycheck.com, accessed September 2026
• IndiaFilings, GreenJams Buildtech Private Limited company record (CIN U45400AP2019PTC113262) — indiafilings.com, accessed September 2026
• The Better India, “Engineer Makes Carbon-Negative Bricks That Cut Construction Cost By 50%” — thebetterindia.com, July 2021
• The Better India, “Civil Engineer Upcycles Stubble into Carbon-Negative Bricks” — thebetterindia.com, 2023
• BiltraxMedia, “GreenJams: Tackling carbon footprints” — biltraxmedia.com, August 2021
• Construction World, interview with Tarun Jami — constructionworld.in, June 2026
• MIT Solve, GreenJams solution submission — solve.mit.edu, June 2021
• Third Derivative, GreenJams portfolio profile — third-derivative.org, accessed September 2026
• Business Standard / ANI, “Swachhata Startup Challenge winners receive Rs 25 lakhs grant from MoHUA and AFD” — business-standard.com, September 2022
• IBEF, “Green Building Materials: Cutting India’s Emissions” — ibef.org, January 2026
• UNEP, Global Status Report for Buildings and Construction 2025–2026 — unep.org, 2026

Found an error? Write to us and we’ll correct it in the open, dated, on the piece.