Revised 23 September 2026 · v1.2.0 · what changed

CORSIA, the International Civil Aviation Organization's Carbon Offsetting and Reduction Scheme for International Aviation, only counts a fuel as a Sustainable Aviation Fuel (SAF) if its full lifecycle carbon intensity sits at least 10% below a fossil-jet baseline of 89 gCO₂e/MJ. That test runs on default values published by ICAO-approved certification schemes, one feedstock and process at a time. Run India's most heavily promoted ethanol feedstock through it, and the fuel that comes out the other end does not merely fail to help — on the certification scheme's own default number, it is dirtier than the fossil jet fuel it would replace.

The number that doesn't survive contact with the table

Reading ISCC CORSIA 205 "Life Cycle Emissions" v2.0 — the document by which ISCC, an ICAO-approved Sustainability Certification Scheme, reproduces ICAO's own default carbon-intensity tables — the alcohol-to-jet (ATJ) route via the ethanol pathway gives corn/maize grain a default core-plus-indirect-land-use-change value of 90.8 gCO₂e/MJ using US assumptions, or 100.6 gCO₂e/MJ on the global default. Both sit above CORSIA's 89 gCO₂e/MJ fossil-jet baseline. A fuel has to come in at least 10% below that baseline to qualify as a CORSIA Eligible Fuel at all; corn ethanol's own default doesn't merely miss the 10% cut, it doesn't clear the baseline in the first place. This is a default value from the certification scheme's own published table, not a modelled estimate from this piece.

MoPNG has been promoting exactly this feedstock

The Ministry of Petroleum and Natural Gas has actively promoted maize as an ethanol feedstock since a PIB release in November 2023, and this blog has separately documented how far that push has gone on the road-fuel side: distilleries used about 12.6 million tonnes of maize for ethanol in the 2024-25 supply year, roughly 29% of that year’s crop, by the government’s own figures, a diversion this blog traced through to a documented rise in egg prices via the poultry-feed market — see The Diesel Truck Isn't Why Your Eggs Cost More. The Ethanol Tank Is and India Hit E20 on Maize and Rice, Not Sugarcane (this blog's own reporting). None of that ethanol is currently being converted to jet fuel at scale — India's SAF programme today runs overwhelmingly on used cooking oil, not grain ethanol. But if maize-ethanol capacity built for the road-fuel mandate were ever redirected toward SAF, CORSIA's own default table says that specific fuel would not qualify. The maize-ethanol build-out and the SAF programme are, on the numbers, pointed in opposite directions.

Molasses passes — through a route India doesn't use

The confusion compounds when the feedstock is India's dominant one, cane molasses. Molasses does not appear at all in CORSIA's ethanol-to-jet default table — it has no listed default value on that specific route. It does appear, with a default value, on the isobutanol-to-jet route: 34.3 gCO₂e/MJ (Brazil default) to 36.1 (global default), a roughly 59–61% cut against the 89 baseline, comfortably clearing the bar. The catch is that India's ethanol industry is built around ethanol, not isobutanol — this blog has covered separately why the world's ATJ plants, and India's own limited alcohol-to-jet efforts, lean on ethanol rather than isobutanol despite isobutanol being certified two years earlier; see India Wants Isobutanol in Both Diesel and Jet Fuel. It Has Built a Domestic Supply Chain for Neither (this blog's own reporting). A molasses-to-ethanol-to-jet producer in India cannot simply cite a default value the way a molasses-to-isobutanol-to-jet producer could; it would have to run a full actual-value lifecycle calculation through an approved certification body instead — a real cost and audit burden that has nothing to do with molasses actually being a dirty feedstock, and everything to do with which named chemical route a plant is built around.

India's SAF regulatory stack, so far

India's targets sit at the slow end internationally and apply only to international flights: the EU runs 2% in 2025 rising to 6% by 2030 and 70% by 2050; the UK runs 2% in 2025 to 10% by 2030; Japan targets 10% by 2030; Singapore runs 1% from 2026 to 3–5% by 2030. India has no domestic-flight SAF mandate notified at all, and no SAF-specific national policy — SAF is not integrated into the National Policy on Biofuels 2018, entering only implicitly through that policy's "drop-in fuels" definition.

The feedstock India can actually use today is mostly wasted

Used cooking oil (UCO) is the only feedstock behind India's certified SAF production so far — IOCL Panipat's certification runs on it. India generates an estimated 1.8–2.6 million tonnes of UCO a year, of which only 110,000–156,000 tonnes, roughly 6%, is collected for reuse of any kind; the remaining 94% is uncollected, and a further share of what is collected re-enters the food chain or is exported rather than converted to fuel. Meeting even the 5%-by-2030 international target is estimated to need roughly 0.4–0.5 million tonnes of SAF annually — a quantity that dwarfs current UCO collection rates. Agricultural residue is the larger long-term resource (roughly 230 million tonnes of surplus residue, on the government's own figure), but converting residue to jet fuel needs Fischer-Tropsch gasification or advanced cellulosic alcohol-to-jet technology that has no commercial-scale plant in India yet; first-of-a-kind Indian SAF plants beyond simple co-processing are not projected before 2029, after both the 2027 and 2028 targets fall due.

What's changed at ICAO since these defaults were set

ICAO's default life-cycle emissions table has moved twice since ISCC CORSIA 205 v2.0 (December 2023) reproduced it. A 7th edition (June 2025) incorporated the most recent IPCC 2019 emission factors, removed the effect of soil-carbon accumulation from land-management practices on reported carbon intensity, and refined the energy-yield calculations specifically used for ATJ-ethanol pathways — the exact route corn/maize and molasses ethanol run through. An 8th edition, approved by ICAO on 19 November 2025, went further: it added a default core-LCA value for the palm-oil-mill-effluent (POME) HEFA pathway for the first time and broadened default ILUC coverage to additional feedstocks including miscanthus, switchgrass and poplar.

The list of bodies allowed to certify SAF against these tables has also moved. ISCC and RSB were both approved as CORSIA Sustainability Certification Schemes in June 2023; ClassNK was added in October 2024, specifically for economic operators evaluated against Chapter 2 of the CORSIA Sustainability Criteria. A Fourth Edition of ICAO's "Approved Sustainability Certification Schemes" list was published in June 2026 — after the India regulatory dates and the ISCC document this piece's core figures trace to — so any current, complete list of approved bodies should be checked against that edition rather than assumed static.

What would fix this

• Rule maize ethanol out of SAF policy explicitly, in writing, now. Nothing currently stops maize-ethanol capacity built for the road-fuel mandate from being pitched at SAF investors or procurement programmes; an explicit statement that it does not qualify under CORSIA's own default values would prevent capital being misallocated toward a route that cannot be certified as built.
• Get an actual-value CORSIA calculation done for molasses-ethanol-to-jet, once, and publish it. A single approved-body actual-value study, done centrally and made public, would let every Indian molasses-ethanol producer cite a validated number instead of each commissioning its own audit from scratch.
• Publish a UCO collection target with a funded mechanism, not just a feedstock estimate. A 94%-uncollected figure restated every year without a collection-infrastructure plan attached is a fact, not a policy.
• Name a domestic-flight SAF trajectory, even a modest one. International-only targets leave the much larger domestic aviation market with no signal at all to plan capacity against.

These are proposals from this blog, not recommendations any agency has adopted.

A widely-used SAF calculator gives maize a very different number. That's not a contradiction — it's the whole problem in miniature

Airlines and fuel buyers commonly work from simplified SAF emissions calculators built around IATA's own SAF Accounting and Reporting Methodology, released 31 January 2025, which airlines use to calculate the emissions credit they can claim for SAF they have already purchased and burned: ER = EF × [mSAF × (1 − LCASAF / LCACAF)], where LCA_CAF is the same 89 gCO₂e/MJ conventional-fuel baseline this piece has used throughout. One such calculator, built around that formula, lists a feedstock-default LCA value for maize via alcohol-to-jet of just 43 gCO₂e/MJ — a 52% cut against the 89 baseline, comfortably passing, and starkly different from the 90.8–100.6 gCO₂e/MJ default this piece has cited from ISCC's reproduction of ICAO's CORSIA table.

Both numbers can be genuine and still describe different things. Published life-cycle literature on corn-ethanol-to-jet is itself a wide range: one 2025/2026 Applied Energy techno-economic study puts a baseline Gen-1 corn-grain design at a total of 69.1 gCO₂e/MJ (51.7 from ethanol production including ILUC, plus 16.7 from the ethanol-to-jet upgrading step), while other published estimates for various ATJ-corn-ethanol plant configurations run from roughly 35 to 55 gCO₂e/MJ depending on process design and how indirect land-use change is treated. The CORSIA/ISCC default sits well above all of these because ICAO's own methodology applies a specific, deliberately conservative ILUC calculation to crop feedstocks that some academic and industry models either omit, discount, or apply differently.

The same calculator's other feedstock defaults are less contentious and worth citing on their own merits: rice straw via gasification and alcohol-to-jet at 15 gCO₂e/MJ (an 83% cut, no land-use conflict), and municipal solid waste via gasification at 20 gCO₂e/MJ (a 78% cut) — both directionally consistent with the FT/gasification route's strong CORSIA performance already established earlier in this piece, though this piece could not independently verify those two specific decimal values against a primary ICAO or ISCC table the way it did for the corn-ethanol figures. Rice straw's India-specific case is strong on scale alone: Punjab generates roughly 19–20 million tonnes of paddy straw a year on its own, independently confirmed via NGT and CEEW reporting on the state's stubble-burning crisis, most of which is currently burned rather than converted to any use.

What this piece does and doesn't cover

• The CORSIA/ISCC default values above trace to ISCC CORSIA 205 v2.0 (December 2023), not the current 8th edition (November 2025). See the dedicated section above on what changed between editions and why this piece could not pull the revised numbers directly; the structural findings (corn ethanol fails, molasses has no ethanol-route default) are independent of which edition is current, but the exact decimals are not guaranteed to match today's table.
• This piece does not model the cost side of SAF pathways (production cost, market price, or the case for India's PBtL biomass-plus-green-hydrogen route, which independent modelling puts below the global SAF cost benchmark but which has no commercial plant operating anywhere) — that is a separate piece of analysis this blog may cover on its own.
• PNGRB has no role in SAF regulation. ATF marketing runs through MoPNG's ATF Control Order, 2001, and SAF oversight sits with DGCA (CORSIA compliance), MoPNG (marketing) and BIS (fuel specification) — worth stating plainly since this blog has covered PNGRB extensively on adjacent gas-sector topics.
• The rice-straw and MSW LCA defaults (15 and 20 gCO₂e/MJ) cited above come from a single calculator tool's feedstock-reference table, not from a primary ICAO/ISCC document this piece read directly, unlike the corn-ethanol and molasses figures earlier in this piece. Treat them as illustrative and directionally consistent with the gasification route's known strong CORSIA performance, not as verified certifiable defaults.

Sources: ISCC CORSIA 205 "Life Cycle Emissions" v2.0 (Dec 2023), the ICAO-approved certification scheme's published reproduction of ICAO's default lifecycle-emission tables, cross-checked independently via web search against the same 90.8 gCO₂e/MJ US default figure and the 89 gCO₂e/MJ CORSIA baseline. India regulatory stack per PIB releases 1979705 (25 Nov 2023), 2163273 (3 Sep 2025) and 2255021 (23 Apr 2026), and Cotecna India's own certification announcement for IOCL Panipat, independently cross-checked. India SAF blending targets (1%/2027, 2%/2028, 5%/2030) independently confirmed via Minister of State for Civil Aviation Murlidhar Mohol's parliamentary statement, as reported in trade press. UCO collection figures per SAF Association reporting (Sept 2026, via Tribune India/ANI). GREET-model alternative corn-ethanol CI figure per Resources for the Future analysis, cited here as a caveat, not as the operative CORSIA-certifiable number. Edition history and methodology changes per ICAO's own document 06 series (7th edition, June 2025; 8th edition approved 19 November 2025) and trade-press summaries of those editions (Vurdhaan Aviation Regulatory updates), independently searched but not directly fetched, since icao.int and third-party mirrors both blocked automated access from this piece's research environment on repeated attempts. CORSIA Sustainability Certification Scheme approval dates (ISCC and RSB, June 2023; ClassNK, October 2024) and the existence of a Fourth Edition approved-SCS list (June 2026) per ICAO's own document 04 series and IATA's CORSIA fact sheet (June 2026). The 85%-of-2019-emissions sector offsetting baseline and the 2027-2029 offsetting phase's approved credit programmes (Gold Standard, Verra) per ICAO's 41st Assembly resolution and GreenAir News/Norton Rose Fulbright market-update coverage — cited only to distinguish this separate mechanism from the fuel-eligibility baseline this piece is otherwise about. IATA's SAF Accounting and Reporting Methodology (released 31 January 2025) and its emissions-reduction formula per IATA's own press release and independent trade-press coverage (Biomass Magazine, Ethanol Producer Magazine), both cross-checked against the same formula appearing in a user-supplied feedstock calculator spreadsheet built around it. The 69.1 gCO₂e/MJ Gen-1 corn-grain ATJ figure and the 35–55 gCO₂e/MJ literature range per an Applied Energy techno-economic and life-cycle analysis (2025/2026) and related OSTI-indexed studies, independently searched. Rice straw's Punjab-specific generation figure (~19–20 million tonnes/year) per NGT proceedings reported in Business Standard and CEEW's published crop-residue-management research, independently cross-checked. A related World Resources Institute India report, "Sustainable Aviation Fuel in India" (WRI India, dated 25 March 2026, documenting a 29 May 2025 New Delhi roundtable), was identified and confirmed to exist but could not be fetched directly for this piece — wri-india.org is blocked from this piece's research environment on the same automated-access basis as icao.int.

About this article: Researched, written and edited by Umashankar Triplicane Dwarakanathan, with AI research assistance; every figure is meant to trace to the primary source cited. See the Editorial Policy for how sourcing, AI use and corrections work.