LONDON (AP) — Campaigners fighting British government plans to expand Heathrow Airport have lost a challenge in one of the country's highest courts.

A coalition of local councils, environmentalists and London residents claim the government has failed to properly address the impact on air quality, climate change, noise and congestion that adding a third runway would entail. London Mayor Sadiq Khan has also backed the lawsuit.

The environmental group Greenpeace says that while the campaigners may have lost this judgment, the government is losing the argument on whether such expansion is "morally justifiable." 

Parliament approved plans last year for the third runway, backing what the government described as the most important transportation project in a generation.

Prime Minister Theresa May has said the expansion will boost economic growth.