Mercedes-Benz India has issued a customer advisory after YouTuber Sourav Joshi claimed his GLC 300 4MATIC's mileage crashed from around 16-17 kmpl to nearly 5 kmpl within 48 hours of switching to E20 petrol. The carmaker says the drop has more to do with what's coming out of the pump than what's in the tank.

The episode matters beyond one viral video. India’s E20 rollout accelerated through 2025, with the blend becoming the standard fuel at most pumps by the end of the year, and around 20 crore two-wheelers and 20 lakh four-wheelers now use it, per Union Petroleum Minister Hardeep Singh Puri. If a viral anecdote can trigger this much doubt, most car owners deserve to know what's actually driving mileage complaints.

What Joshi claimed

Sourav Joshi, a YouTuber with over 41 million subscribers, made the claim in a vlog titled "Race With Brothers Kon Jeetega?", saying his Mercedes' mileage nearly cratered after a fill-up of E20 fuel. In the clip, he joked, "It is a Mercedes after all. I'll have to send it to Delhi if a problem arises," per Business Today.

Former Delhi Chief Minister Arvind Kejriwal amplified Sourav Joshi's claim by sharing a similar complaint from another car owner, saying he'd spoken to Delhi mechanics and vehicle owners reporting long queues of cars with E20-linked issues. He called on the government to stop "forcing E20" on consumers, according to the Free Press Journal.

Sourav Joshi has since deleted the vlog segment with the mileage claim. A social media post suggesting "Mercedes should sue him" gained traction online, though Mercedes-Benz has not responded to that demand or signalled any legal action, per Free Press Journal.

Mercedes-Benz's response

In its advisory, Mercedes-Benz India said all its petrol BS VI vehicles are materially compatible with E20 and have been certified by the relevant authorities, adding that customer safety and vehicle reliability remain its top priorities, the Free Press Journal reported.

MD and CEO Santosh Iyer went further in comments to Autocar India, saying the company has seen a rise in E20-related customer queries and has equipped its dealer network with FAQs to handle them. He said Mercedes was among the first automakers to get materially E20-compliant cars, and that its new S-Class hybrid is already built for E25, the next step up in ethanol blending.

Iyer clarified that Mercedes-Benz vehicles made from 2020 onwards are E20-compliant, with 2023-24 models meeting the latest ethanol standards. For Mercedes-Benz petrol BS VI vehicles, the company says no customer modification is required for E20 use, he said, per Forbes India.

The 0.6 km/l number that matters

Here's the figure that undercuts the viral panic: Iyer said the real-world mileage hit from E20 is small, roughly 0.6 km for a car that otherwise gives 20 km per litre. Driving habits and maintenance, he said, affect mileage far more than the fuel blend itself.

That's a fraction of the drop Sourav Joshi described, from 16-17 kmpl to nearly 5, a fall of more than two-thirds. If E20 alone caused only a 3-4% dip, something else was likely behind the rest.

Iyer pointed to that something else directly. "We have seen increased fuel adulteration happening under the garb of E20, which is also causing concern because we have some customers who may not have filled the right quality of fuel," he told Autocar India. He called for stronger enforcement from regulators to separate genuine ethanol-related issues from fuel that's simply been cut with something it shouldn't have.

The government's side

Puri had already dismissed the broader E20 backlash as a "misrepresentation" before the Iyer interview, saying automakers and service providers report no widespread difficulty with the blend, per Business Today. Concerns over fuel quality and supply have run through Indian energy policy all year, from ethanol blending debates to worries over LPG supply after tensions in West Asia, underscoring how closely Indians now track what's actually in their tanks and cylinders.

For now, the practical takeaway for owners is simple: a sudden, dramatic mileage crash should not be blamed on E20 alone without checking fuel quality, driving pattern, service history and the vehicle’s own diagnostics. E20 may reduce mileage slightly, but the kind of fall described in viral posts needs a proper inspection before anyone calls it an ethanol problem.