Dibya R, a resident of Bhubaneswar, Odisha, has been riding his Royal Enfield Meteor 350 since 2022, clocking 42,000 kilometres in four years, all of which he said was through steady, comfortable riding, with no history of harsh use. For most of that time, the bike could deliver a reliable 40-41 kmpl. But over the past two to three months, that mileage dropped sharply, hovering between 36-39 kmpl.

Puzzled by the decline, Dibya inspected his entire motorcycle, including the inside of his fuel tank. Shining his phone's torch through the tank opening, he found patches of rust creeping across the metal surface.

His authorised Royal Enfield dealership attributed it to the fuel itself and offered a fix of a full fuel tank replacement at a cost of around Rs 19,000. When Dibya asked for this assessment in writing, the dealership refused.

In Haryana’s Hisar a similar story played out with Yuvraj Taneja’s car. His 2023 Volkswagen Virtus, driven nearly 27,000 km over close to three years, had never given him any trouble. This was until last month, when it suddenly stalled on the road, throwing up an EPC warning, an Auto Start-Stop error, and the engine check light together.

"The car wouldn't start for 15-20 minutes, then briefly ran before cutting out again," he told The Core.

Roadside assistance towed the car to an authorised dealership, where technicians traced the fault to a blocked fuel injector and cleaned it for Rs 2,000, after which the car ran fine. What struck Yuvraj was the timing, as he had got the car serviced just 20 days earlier.

Dealership officials pointed to possible fuel adulteration. It's an answer he still finds hard to accept, because he'd been filling up at the same petrol pump since he bought the car.

The evidence has not moved the government's public position though. Union Minister for Road Transport and Highways Nitin Gadkari has rejected claims that E20 petrol damages vehicles. "I challenge anyone to show me a single petrol vehicle that has been corroded because of ethanol," he said.

In Mumbai, Gigi Dcruz had just filled the tank of her Kia Sonet last week, which she bought in October 2023, and is E20-compliant by design. But the car stalled five minutes after she left the petrol pump and refused to restart.

"When we got back to the petrol pump, we realised many other people had the same complaint," she told The Core.

Dcruz spent the rest of her day at the pump, calling the police, having the fuel tank drained, and getting a fresh batch of premium fuel filled in its place. The car started roughly 30-40 minutes later.

"I had to spend my entire day dealing with this, and pay to get the fuel drained, refilled, and the car towed. Not everyone can afford to leave work and deal with this," she said. "The government should give consumers a choice in this, not mandate it."

Three owners, three states, three different failure modes, but one common thread — vehicles malfunctioning after being filled with the mandated fuel.

All vehicles sold after April 2023 are E20-compliant, and from April 2026, E20 is the standard fuel available nationwide. Now, millions of vehicles on Indian roads today were bought, registered, and taxed before 2023, under a fuel standard that no longer exists at the pump. Their owners paid in full for a vehicle that was fully compliant with the law at the time of purchase.

One policy shift later, they are the ones absorbing the cost in mileage and in repairs of a fuel standard that didn't exist when they signed the papers. That, more than any single technical dispute, is the issue here — who pays for the fuel transition it demands?

The Mileage Question

A drop in mileage was always going to be part of the story, and it has been the most visible consumer complaint since the rollout began. That is because the energy content or the calorific value of E20 is less than that of pure petrol.

The government has accepted that there could be a 3-5% reduction in fuel economy. But put that figure against what owners are actually reporting, and the gap is hard to ignore.

A recent survey by citizen pulse aggregator LocalCircles found that 66% of petrol vehicle owners reported a mileage drop of over 10%, roughly three times what the industry's own numbers concede.

In the survey, 53% of respondents rated the E20 rollout as "disastrous" or "ineffective," with 42% calling it outright "disastrous," against just 13% who rated it positively.

Separately, 45% reported a moderate to major rise in wear and tear or repair needs, and 31% said they'd want the option to revert to E0 or E10 petrol, even at a higher cost.

Who's Seeing The Damage, And Who Isn't

Industry body Federation of Automobile Dealers Associations (FADA) said it had not come across any case of a vehicle malfunctioning because of E20 fuel yet.

CS Vigneshwar, President of FADA, further told The Core last week that since FADA is not a testing association, it has “full faith in the OEMs whom we buy these vehicles from, and also the government, which laid down the rules and regulations. So when they have assured us, we will take it."

However, not everyone in the trade shared that confidence. According to the car servicing platform GoMechanic, some older petrol vehicles have components originally engineered for lower ethanol blends.

The company spokesperson told The Core that fuel lines, rubber seals, gaskets, O-rings, and certain other fuel system components can see accelerated wear after prolonged exposure to higher ethanol concentrations.

Fuel filters and injectors may also need more frequent checks, since ethanol's cleaning properties can loosen deposits that have settled in older fuel systems, a plausible explanation for the kind of injector blockage that stalled Taneja's Virtus.

The underlying issue, said a veteran automotive engineer who has worked in R&D and product engineering at one of India's top three automakers, is that higher ethanol blends demand material compatibility, engine tuning and optimisation that simply wasn’t engineered into older-generation vehicles, because E20 was not a fuel standard when they rolled off the assembly line.

"We are getting a lot of calls from several customers, as there is a lot of stir around the consequences of the E20 fuel. There is no solution to this right now," said Raju, a Delhi-based mechanic, who added that if the government doesn't revisit the mandate, the cumulative damage to vehicles could grow over time.

Maruti Suzuki, for its part, pointed to scale as reassurance. The country's largest carmaker said it had serviced more than 1.5 crore older cars over the past two years that were not E20-certified, and had found no fuel-related problems.

"As a manufacturer, we have tested E10 cars, which were prevalent before 2023, on E20 fuel for all parameters, and we have not found anything of concern," Rahul Bharti, Maruti Suzuki's senior executive officer for corporate affairs, said at a press briefing on July 4. Most vehicles manufactured in India between 2011 and 2020 were built to be E10-compliant.

The joint press conference brought together government officials and automakers, including Maruti Suzuki, Hero MotoCorp, and Toyota Kirloskar Motor, who struck a reassuring note, saying even older-generation vehicles which are E5 or E10 compliant can also run safely on E20.

While the record is split, both sides can be true, reflecting that the large-scale averages have not yet shown a systemic failure, but a meaningful subset of owners are experiencing real and costly incidents.

Even the government advisory body had flagged the gap. In an earlier report, NITI Aayog recommended that the continued availability of E10 fuel for older, non-compliant vehicles be ensured alongside the E20 rollout, a recommendation that the blanket E20-only rollout at the pump does not currently reflect.

How Other Countries Did It

India has been promoting ethanol blending in fuel in various forms since 2003. However, the push was accelerated after the National Policy on Biofuels was revamped in 2018. The policy achieved its 20% ethanol blending target by July 2025, five years ahead of the original 2030 deadline.

Brazil and the US, the world's largest ethanol producers, made the shift decades ago. And several other countries have followed.

However, India is possibly the first to run into this particular problem of a nationwide fleet with millions of older, non-E20-certified vehicles still on the road, transitioning to the new fuel almost unprepared, with no fallback grade available at the pump.

Even Brazil, held up worldwide as an ethanol-blending success story, offers consumers a choice of blend levels at the pump, unlike India's blanket rollout of E20.

"Brazil's success is rooted in consumer choice and pricing dynamics, as their market dynamically prices ethanol against gasoline, so consumers are economically incentivised to choose higher blends at the pump,” Joshua Wycliffe, director of the Global Biofuel Alliance (GBA), told The Core.

“Their seamless integration of flex-fuel vehicles, which now dominate the light-vehicle market, shows how automotive policy and energy policy can work hand-in-hand to build consumer confidence," he added.

The US, by contrast, has largely stayed limited to E10 as standard. Wycliffe noted the US Renewable Fuel Standard gives producers and investors a long-term, predictable mandate to scale operations, backed by real investment in retail infrastructure like blender pumps, letting consumers safely choose their blend level, whether that's E15 or E85.

So What Actually Fixes This?

There are really only three paths forward: rely on chemical additives, introduce retrofit kits, or roll back the E20 mandate and offer choice to the consumers.

Additives are the easiest to dismiss. They can offer some protection, but they do not touch the deeper compatibility issue.

Retrofit kits sound like the practical middle ground, but the reality is closer to a partial engine overhaul than a quick fix.

While manufacturers can execute this kind of work on an assembly line, under controlled conditions, with precision tooling and quality checks, replicating that same standard across millions of vehicles already running on Indian roads, in workshops of wildly varying quality, across cities and villages alike, is an entirely different scale of challenge.

"For nations with a large base of legacy vehicles, certified retrofit solutions can theoretically accelerate the use of higher ethanol blends without waiting for a complete fleet turnover," Wycliffe said.

But he was careful to flag the conditions attached to that — such technologies need stringent standardisation and certification frameworks. Without rigorous testing for safety, engine durability, and emissions compliance, unregulated retrofits could produce suboptimal vehicle performance, which could, in turn, damage consumer confidence in biofuels more broadly.

"So while retrofits can serve as a supplementary measure, the global consensus still leans toward factory-fitted E20+ and flex-fuel vehicles as the most reliable, efficient, and consumer-friendly path to long-term ecosystem stability," he said.

GoMechanic echoed the caution that retrofitting or replacing components should never be approached as a one-size-fits-all solution.

"As a service network, we believe the focus should be on enabling informed decisions rather than promoting retrofits indiscriminately,” the company said, adding that for older vehicles it recommends following manufacturer guidance and staying on top of preventive maintenance so wear or compatibility issues surface early.

Manufacturers, including Maruti Suzuki and Hero MotoCorp, were earlier known to be working on retrofit kits. That work hasn't translated into anything available to consumers, though. "There is no such kit that we are offering in the market, (it is only) for R&D purposes," Bharti said recently.

A genuine retrofit means new fuel lines, fuel pump changes, and gas kit modifications. Fuel lines are relatively manageable to replace but gas kits are where things get genuinely difficult to retrofit safely at scale.

And the challenge isn't purely technical; it needs trained technicians in sufficient numbers, someone willing to take responsibility for the quality of that work across thousands of scattered workshops, and, critically, someone to pay for it. None of that infrastructure currently exists at the scale this transition would require.

Meanwhile, the government has ruled out giving consumers a choice of fuel at the pump. It said that public sector banks have financed close to Rs 1 lakh crore a year in ethanol plants, storage, and logistics, and reverting to E10 now would strand that investment.

The Real Question

While there is no dispute about India’s need to move towards renewables for energy security, what is unresolved is who pays for the transitional damage when the mandate meets a fleet that was never built for it.

Dibya paid road tax on a bike engineered for a different fuel standard, and is now being quoted Rs 19,000 for a fuel tank the dealership won't put its assessment of in writing. Taneja got a service 20 days before his car stalled on the road.

Dcruz lost a working day and paid out of pocket to get her tank drained at a pump where she wasn't the only one it happened to. In each case, the cost of the transition landed on the owner, after the fact, for a decision they had no part in making.

Until the government, the industry, and consumers arrive at a shared answer for who absorbs that cost, and until there's a fleet-wide, independently verified picture of how older vehicles are actually faring, the frenzy playing out on Instagram, X, and YouTube isn't likely to fade.