THE HAGUE, Netherlands (AP) — A judge ruled Wednesday that the Dutch government cannot order Amsterdam’s Schiphol Airport, one of Europe’s busiest aviation hubs, to reduce the number of flights from 500,000 per year to 460,000, dealing a blow to efforts to cut emissions and noise pollution.

The ruling came in a summary case brought by airlines and civil aviation organizations led by Dutch carrier KLM that sought to halt the planned cuts unveiled last year.

The decision by a judge in Haarlem, a city close to Schiphol, came a day after the airport announced plans to phase out all flights between midnight and 5 a.m., ban private jets and the noisiest planes, and abandon a project for an additional runway.

The judge ruled that the Dutch government did not follow the correct procedure when it called on Schiphol to reduce flight numbers, a decision that was hailed last year as a breakthrough by environmental groups.

Wednesday’s decision means that Schiphol “may not reduce the maximum number of flights … to 460,000,” the court in Haarlem said in a statement.

In response, KLM said it plans measures that offer “a better alternative for achieving less noise and CO2 while meeting travelers’ need to fly.”

The airline said it would explain its approach in the next phase of the case. “This will investigate whether noise levels can be reduced around Schiphol using methods other than those envisaged by the ministry,” KLM said.

The government ministry responsible for aviation infrastructure said it was studying the ruling and considering its next steps.

The ministry said in a written reaction that it is “striving to find a new balance between the interests of residents and the living environment on the one hand and the economic importance of Schiphol for the Netherlands on the other.”

U.S. carrier Delta Air Lines welcomed the ruling, saying it safeguarded Schiphol’s future.

“Delta believes that it is possible to balance sustainability priorities with passengers’ desire to travel and connect with people across the world — something we have demonstrated through a vigorous commitment to fleet renewal and other practices to help decarbonize our operations and reduce noise,” Peter Carter, Delta’s executive vice president for external affairs, said.

International Air Transport Association Director General Willie Walsh said the judge “understood that the Dutch government violated its obligations in short-cutting processes that would bring scrutiny to its desire to cut flight numbers at Schiphol.”

Environmental organizations, meanwhile, issued a joint statement expressing their disappointment.

“Major polluter KLM is giving a slap in the face to local residents, the climate and the government that saved the company from bankruptcy,” groups including Greenpeace and Friends of the Earth said. “This ruling may cause a delay, but Schiphol will shrink. We are convinced of that. The government has now also started the correct procedures for this.”