The US is set to ease proposed yearly requirements to the end of 2030 of its sweeping plan to aggressively cut tailpipe emissions and boost electric vehicle sales, two Reuters sources said.

The news agency noted automakers and the United Auto Workers had urged the Biden administration to slow the proposed ramp up in EV sales because EV technology was still too costly for many mainstream US consumers and more time was needed to develop charging infrastructure.

According to the report, the Environmental Protection Agency in April 2023 had proposed requiring a 56% reduction in new vehicle emissions by 2032. Under the initial EPA proposal covering 2027-2032, automakers were expected to aim for EVs to constitute 60% of their new vehicle production by 2030 and 67% by 2032 to meet stricter emissions requirements.

Under the revised final regulation expected to be made public as soon as next month, the EPA would slow the pace of its proposed yearly emissions requirements to the end of 2030. The new pace was expected to result in EVs accounting for less than 60% of total vehicles produced by 2030, the Reuters sources said.

The UAW has said the EPA proposal should be revised to increase stringency "more gradually" and occur over a "greater period of time", Reuters added.

The Alliance for Automotive Innovation (AAI), a trade group representing several automakers, last year called the initial EPA proposal "neither reasonable nor achievable" and urged "adopting requirements for 40% to 50% (electric, plug-in electric and fuel vehicles) in 2030", the report added. EVs accounted for about 8% of sales in 2023.

An EPA spokesperson told Reuters the proposal remained under interagency review and that it planned to finalise a rule that is "readily achievable, secures reductions in dangerous air and climate pollution and ensures economic benefits".

The EPA was also expected to address other concerns raised by automakers including a proposal to drastically reduce particulate matter from petrol powered vehicles, which the industry has argued would effectively require gasoline particulate filters on every petrol-powered vehicle, Reuters added.