LUXEMBOURG (Reuters) – A European Union court upheld on Thursday a complaint by the city authorities of Paris, Brussels and Madrid against an EU rule change on vehicle emissions they said had increased pollution, and it partly overturned the regulation.

The General Court said the European Commission’s 2016 regulatory amendment raising the limits on nitrogen oxide emissions from cars and vans went beyond the powers of the EU executive and broke EU human rights and other laws.

“The General Court upholds the actions brought by the cities of Paris, Brussels and Madrid and annuls in part the Commission’s regulation setting excessively high oxides of nitrogen emission limits for the tests for new light passenger and commercial vehicles,” it said in a statement.

“The Commission did not have the power to amend the Euro 6 emission limits for the new real driving emission tests.”

The French, Belgian and Spanish capitals have imposed their own local restrictions to curb air pollution, the Court said, and notably the oxides of nitrogen, collectively known as NOx, emitted especially by older diesel engines.

It said only the part of the Commission’s Regulation 2016/646 which sets NOx limits must be annulled, not other parts of the legislation, which sets out the conditions for testing.

It gave the Commission a year to make the amendments, so as to avoid legal uncertainty over decisions made already by consumers and carmakers.

The Court dismissed a claim for damages of a symbolic euro brought by the City of Paris. The French capital said the Commission action had hurt its image. The Court said no damage was proven and if there were, it would be compensated for by the annulment of the regulation.