Plans for a third runway at London’s Heathrow Airport have been given a new boost after the airport’s owner won a Supreme Court challenge Wednesday. The latest ruling clears a hurdle for Heathrow, but there are still more in the way.

Any planning decisions on the project will have to show they are compatible with the government’s commitments to addressing climate change, including its Net Zero commitment to remove almost all carbon emissions from the economy by 2050.

The Appeal Court had blocked the project earlier, ruling that the government failed to take account of its climate commitments when it approved the expansion plans.

Heathrow Airport Ltd., which owns and operates the airport, challenged that ruling. The Supreme Court overturned it Wednesday and ruled that the runway plans were lawful.

The expansion of Heathrow, one of Europe’s busiest airports, has been a controversial project for over a decade. Environmental groups have long campaigned against it, raising concerns including the impact on air quality and noise pollution.

Green campaigners said Wednesday’s outcome was “incredibly disappointing” but insisted there “remains real doubt” about whether the third runway will ever happen.

Heathrow said the ruling was “the right result for the country.” The airport said it has “already committed to net-zero and this ruling recognises the robust planning process that will require us to prove expansion is compliant with the U.K.’s climate change obligations, including the Paris Climate Agreement, before construction can begin.”

“Demand for aviation will recover from COVID-19 and the additional capacity at an expanded Heathrow will allow Britain as a sovereign nation to compete for trade and win against our rivals in France and Germany,” it added.