New Delhi, July 20 -- The string of flex-fuel vehicle launches was meant to mark India's next phase of clean mobility. Instead, within weeks, policy moves by the Centre and the Delhi government have raised questions over the future of these vehicles that can run on petrol blended with up to 85% ethanol, fuelling concern among automobile and biofuel makers that policy uncertainty could slow investment and wider adoption of the technology.

On 3 June, Union road transport minister Nitin Gadkari and petroleum minister Hardeep Singh Puri attended the commercial launch of Hero MotoCorp's flex-fuel motorcycle in Delhi, boosting sentiment for the technology's adoption. A day later, India's largest carmaker Maruti Suzuki also launched its flex-fu...