German Chancellor Angela Merkel on Friday admitted to pushing for the delay of a key decision on new rules aimed at limiting car pollution in the European Union.

EU leadership Monday had agreed to a compromise on the deal, which is opposed by large German auto manufacturers. A key decision to endorse the deal, smoothing its passage into law, didn't take place at the meeting Thursday between member states' ambassadors.

"We indeed pushed to not have the vote in Coreper take place," Ms. Merkel said, referring to the committee that deliberated ahead of the two-day European Council meeting.

The proposed rules would require car manufacturers' new fleets to emit an average of 95 grams of carbon dioxide per kilometer by 2020, down from 132.2 grams per kilometer in 2012 and a mandatory target of 130 grams per kilometer in 2015.

Germany 's luxury car makers, such as BMW AG and Daimler AG, argued they would be adversely affected due to the weight and power of their products in comparison with European peers.

Representatives at the Coreper meeting Thursday requested more time to assess details of the new regulation, EU officials said. Ms. Merkel said this was justified due to the short time span from when the compromise was reached Monday.

"We asked for this time and because of that the vote didn't take place," she said.

"I also believe that at a time where we sit here for days and talk about unemployment we also have to be careful--in spite of all the necessities to make progress on environmental preservation--not to weaken our own industrial basis," Ms. Merkel said.