Last July, Britain announced that it was set to halt sales of new diesel and petrol-powered vehicles by 2040, and the British government says it remains steadfast in its aim to achieve that target, despite a recent news report indicating that plans were being watered down from a full policy to a “mission,” Reuters reports.

The plan remains unchanged and is still on track, according to a government source. “We will end the sale of new conventional petrol and diesel engine cars by 2040,” the source told the news agency.

The original outline made last year reportedly did not affect hybrids or plug-in hybrids, but fears have cropped up of late that restrictions may be imposed on these, causing automakers to raise their concerns. However, the source said the ban will not impact hybrids. “It’s not government policy to ban hybrids,” he said.

More details about the plan – which will be known as “Road to Zero” – are set to emerge, but its final unveiling may not be that soon, the source added. The document’s reveal has already been delayed as the country’s transport, business and environment ministries discuss final proposals.

Britain says its pledge to go green on this front is needed because of the impact that poor air quality is having on public health, and authorities are determined to take strong action in the shortest time possible, with plans to implement a number of new measures. France also announced a similar course of action last year, with the sale of new petrol and diesel-powered cars set to be outlawed by 2040.