France is “at fault” for failing to protect a mother and daughter from air pollution they say caused them serious respiratory problems, a court outside Paris has found in a landmark ruling.

The French state had taken insufficient measures against dangerously high atmospheric pollution in the Paris area in December 2016, the most serious surge in damaging fine particles in a decade, concluded the administrative court in Montreuil.

At the time the two plaintiffs were living in the northern Paris suburb of Saint-Ouen, just outside the clogged périphérique ring road, used by more than a million motorists per day.

The case, backed by NGOs, was the first of its kind brought by individuals against the French state over health problems caused by air pollution.

”The state committed a fault by taking insufficient measures concerning the quality of air," the court concluded.

“This is an historic ruling because the responsibility of the state has at last been recognised in an air pollution case,” François Lafforgue, the plaintiffs’ lawyer, told Le Monde. "From now, the state will have to take effective measures.”

However, the court rejected the pair's demand for 160,000 euros (£143,000) in damages, saying it could not find a direct link between their health problems and the state's failings.