* India made E20 fuel mandatory at all petrol pumps at

end-2025

* Car owners complain of mileage drop, potential vehicle

damage

* Government says move lowers imports of crude, helps

farmers

* Modi's political opponents press carmakers for answers

By Arpan Chaturvedi and Aditi Shah

NEW DELHI, July 8 (Reuters) - Indian Prime Minister Narendra

Modi's government is facing mounting anger over a mandatory 20%

ethanol-blended fuel policy, with vehicle owners demanding

choice and an opposition politician asking carmakers Maruti

Suzuki and Toyota ( TM ) to provide clarity.

The 20% ethanol-blended petrol, called E20, became the only

fuel sold at India's 90,000 petrol pumps at the end of last

year, triggering a public uproar that however dissipated within

weeks.

But it's now again at the centre of controversy after a top

government lawyer called E20 an "experiment" in court - and then

backtracked on the comments - re-igniting concerns about the

fuel affecting the performance of cars and what critics called

its hasty rollout.

Hundreds of motorists have posted complaints on X alleging

reduced fuel efficiency and increased wear ​and tear of car

parts from E20. One of the main complaints is that they have no

option to buy unblended petrol if they prefer.

"Auto companies need to stop hiding and tell us clearly ...

can your pre-2023 models actually handle E20 fuel?" said X user

Aashna. "Stop fooling the public."

While countries like Brazil have paced ethanol blend

increases over decades, the U.S. has capped its standard blend

at E10 and sells higher blends only as an option for compatible

vehicles.

In India, however, E20 fuel replaced E10 nationwide in 2025,

well ahead of its 2030 deadline, even though E20-compliant cars

only began hitting the roads in 2023.

Late on Tuesday, opposition politician Arvind Kejriwal held

a press conference during which he read from the owner's manuals

of Maruti and Toyota ( TM ) cars, arguing many old cars were only E10

compliant, tapping into simmering public anger over the policy.

"People are only asking for one thing: please give us an

option," said Kejriwal, a former chief minister of the capital

Delhi. He has written to Toyota ( TM ) and others demanding clarity on

whether their vehicles are E20 compliant, according to letters

he posted on X on Wednesday.

Maruti and Toyota Motor ( TM ) did not

immediately respond to requests for comment.

GOVERNMENT MINISTER CHALLENGES CRITICISM

Reuters has previously reported that a fuel tank flap and

user manual of an Audi Q3 purchased in 2024 in India showed it

recommended only E5 and E10 fuel. The fuel tank of a 2024

Mahindra Scorpio SUV was pasted with a warning

sticker: "CAUTION. PETROL/E10 FUEL ONLY".

Mahindra said in a statement that its E20-compliant vehicles

could use the fuel, but it did not address what would happen

with older cars.

The E20 debate has dominated prime-time television debates

and newspaper editorials in recent days. The government says E20

saves imports of crude oil, helps farmers cultivating sugar, the

base for ethanol, and lowers emissions.

A lawyer filed a new public interest case at the Supreme

Court this week, echoing those concerns. It's not clear if the

court will hear the case amid the new public uproar, given it

dismissed challenges to the policy last year.

Modi's officials and state-run oil companies have been

trying to calm nerves. On Tuesday, Transport Minister Nitin

Gadkari said he was challenging anyone to prove that their

vehicle was damaged because of using E20.

Tehseen Poonawalla, a New Delhi-based entrepreneur and

opposition Congress party supporter, has sought a public

conversation with the minister on the issue, saying he will

bring affected customers to the gathering.