The EU's proposed "Euro 7" law would tighten limits on health-harming pollutants from combustion engine cars.
The European Commission, which drafts new EU laws, has said the health benefits would far outweigh the costs.
However, EU countries and lawmakers - which are in charge of negotiating the final law in the coming months - have each agreed to weaken the rules.
Green lawmakers criticised the vote as a missed chance to reduce the roughly 70,000 premature deaths per year in Europe attributed to vehicle pollution.
"The EU is missing the opportunity to be the future leader in green technology," Green EU lawmaker Bas Eickhout added.
Persons:
Yves Herman, Alexandr Vondra, Bas Eickhout, Adolfo Urso, Kate Abnett, Alvise Armellini, Sharon Singleton
Organizations:
REUTERS, Rights, New, European Commission, Commission, Italy's Industry, EU, Thomson
Locations:
Brussels, Belgium, Rights BRUSSELS, Union, Europe, Italy, Czech Republic