Dutch environmentalists said Tuesday they are suing the government over poor air quality, saying people's "fundamental" rights to good health were being infringed.

In a lawsuit filed on Monday, the Milieudefensie group alleged "the Netherlands exceeds the legal standards for air quality and is violating fundamental human rights by doing too little to combat air pollution."

"This pollution causes thousands of deaths every year, and leaves tens of thousands of people seriously ill. That is unacceptable," added the group's campaign manager, Anne Knol, in a statement.

The suit launched in The Hague is the first step in a lengthy process which could lead to a trial. The first hearing is due to be held on August 17.

Environmental activists say under the constitution "the state has a duty to protect citizens from unhealthy air."

The group alleges that, in tests carried out at 58 sites across the country last year, the levels of nitrogen dioxide exceeded European norms in 11 places.

The indictment has been signed by 57 Dutch citizens, and the lawsuit has been launched after a crowd-funding campaign raised some 30,000 euros ($33,593) to cover the costs.

This latest action comes after another Dutch environmental rights group, Urgenda, last year won a landmark ruling ordering the government to slash greenhouse gases by a quarter by 2020.

Climate experts hailed the June 2015 ruling as "a milestone" in a case brought by 900 Dutch citizens seeking to force a national reduction of the emissions blamed for global warming. The government is appealing.