A panel of experts representing each of the European Union’s 28 member-states have reached an agreement to introduce tougher emissions testing for diesel-powered cars, following Volkswagen’s admission that it had used a “defeat” device to pass U.S. Environmental Protection Agency (EPA) lab tests. The agreement still needs the approval of the European Parliament.

The new tests will require nitrogen oxide (NOx) levels to be measured during special road tests, which will more closely resemble real-world driving conditions, in addition to laboratory conditions.

“The EU is the first and only region in the world to mandate these robust testing methods,” said Elzbieta Bienkowska, EU Commissioner for the Internal Market, Industry, Entrepreneurship and SMEs, in announcing the new rules.

The new rules and testing procedures will only take effect in September 2017 and only for new-model cars. New cars of existing models won’t have to meet the new standards for another two years after that. Moreover, member states agreed that on-road NOx results will be allowed to be twice as high as lab emissions for a 28-month period after the new tests are introduced. Even after that, under the new rules, on-road emissions will be allowed to reach levels 50% over those measured under laboratory test conditions.