After achieving its target of 20 per cent ethanol blending in petrol, the government is preparing to extend its biofuel programme to diesel through isobutanol blending later this year.

Tata Motors is preparing to begin vehicle trials using the proposed fuel blend, with pilot testing expected to commence in the next quarter.

"We will start trial with 2 percent blending of isobutanol; it is being done on a pilot basis. We are working with HPCL to give us the blended fuel so that we can start trials," Tata Motors Managing Director & CEO Girish Wagh said during a press briefing on June 25.

Isobutanol is an advanced biofuel alcohol that can be blended with diesel to reduce emissions, improve combustion and lower dependence on fossil fuels without requiring significant engine modifications.

Wagh said Tata Motors does not expect the initial blending ratio to materially affect vehicle performance.

"Because the calorific value of isobutanol is lower than diesel, there would be some impact but 2 percent is hardly anything to have an impact," he said.

The proposed move follows the rollout of E20 petrol and is aimed at expanding the use of biofuels in the transport sector while reducing India's dependence on imported crude oil.

Last month, Road Transport and Highways Secretary V. Umashankar said a mandate for isobutanol blending in diesel "will start coming in somewhere later this year".

According to data from the Petroleum Planning & Analysis Cell (PPAC), India consumed about 91.4 million tonnes of diesel in FY25, making it the country's most consumed petroleum product.