Ltd, an HPCL subsidiary that is executing the project, has already set up two plants and would set up 24 more plants with a daily capacity to produce 10-15 tons each of CBG using agriculture residue, cattle dung and sewage water, among others, said Mohit Dhawan, chief executive of the subsidiary company.

Since April, India has mandated mixing gas used to run automobiles and cooking gas with 1% of CBG.

This would be gradually raised to 5% by 2028-2029, said Vikas Singh, a director in the federal oil ministry.

He said about 28 million cubic meters a day (MMSCMD) of gas is daily used to run automobiles and in cooking. "We expect this to rise to 44 MMSCMD by 2028-29" Singh said, adding by that time India would have 480 CBG plants, including 195 by state oil and gas companies. India at present meets nearly half of its gas needs through imports of costly liquefied natural gas (LNG). India wants to raise use of gas in its energy mix to 15% by 2030 from the current 6%.