KhetLock

Track: Carbon Markets and Emissions Transparency. KhetLock binds a farm plot and season to independent NASA FIRMS satellite fire evidence on-chain: one plot, one season, at most one attestation credit, minted only when the satellite record shows no fire, and retired exactly once in public.

Climate Impact

Every October and November, paddy stubble burning across Punjab and Haryana produces some of the worst air-quality episodes on earth. Payments and subsidies meant to reward not burning are claimed on the same plot, in the same season, sometimes twice, with weak proof. KhetLock makes the claim auditable end to end: the plot and season are registered on-chain, the satellite evidence pack is hash-anchored, and the credit exists at most once. The same pattern applies to any "pay for a verified absence" scheme: no-burn commitments, deforestation-free plots, methane flaring checks.

Innovation

The chain is not used as a database. It enforces three things a database cannot: uniqueness of a (plot, season) claim across parties who do not trust each other; a check result that cannot be quietly edited after the fact (the passing check cannot be overwritten, and the evidence hash exposes any tampering); and a retirement that is public and irreversible by construction, with the retirement event itself serving as the certificate.

Technical Execution

A single Solidity contract (KhetLockRegistry) on Polygon Amoy: registerPlot, recordCheck (checker-only, pass requires zero qualifying detections), mintCredit (once per plot, only after a passing check), retire (once, certificate event). Ten automated tests cover the golden path and the attack list; all pass. The full demo flow (register, check, mint, retire for three plots) runs from one seed script. The web app needs no wallet to read: plot pages show the map, the evidence pack, the plain-language reason for each outcome, and a live in-browser hash check of the evidence file against the on-chain hash. Contract: 0x76EB24394Ce5BCb2610C5c37bb706727363B26A2 on Polygon Amoy (explorer); the Ludhiana register, check, mint and retire transactions are linked from the contract page.

Practical Usefulness

The users are real: a state agriculture or pollution-control officer verifying no-burn claims before releasing a subsidy, and a carbon buyer who needs a retirement they can show an auditor. Neither needs to trust the farmer's self-report or the platform's database; both can open the public registry and the block explorer and verify the whole history themselves.

Presentation and Communication

The demo video walks the three beats in order: a clean plot attested and minted, a plot with real satellite fire detections rejected with the evidence on screen, and a second claim attempt rejected by the contract itself, followed by a public retirement. Limits are stated in the video and the README: satellite detection thresholds, checker trust in this version, testnet only.