The UK government signed off on London City Airport’s plan to grow passenger numbers by nearly a third, angering environmental campaigners who say it will increase carbon emissions.

The Secretaries of State for Transport and Housing confirmed on Monday they will grant permission for London’s smallest airport to increase passenger numbers from 6.5 million per year to 9 million by 2031.

The new Labour government has said it wants to take a “growth focused” approach to the planning system, and the decision is likely to be a test for how it manages that against environmental concerns. The government’s independent watchdog, the Climate Change Committee has said airport expansion is currently incompatible with the UK’s 2050 net zero goal.

While the government said the airport must maintain an existing 24-hour weekend respite period from 1230 p.m. on Saturday to 1230 p.m. on Sunday, airlines will be able to operate three more flights in the mornings before 7 a.m.

The additional three flights will be restricted to newer and quieter aircraft such as the Airbus SE A220 model and Embraer SA’s E2 jets. 

“While we welcome the approval to increase our passenger numbers, we are disappointed with the Government’s decision to reject our proposal to fly from 12:30 p.m. to 6:30 p.m. on Saturday afternoons,” Alison FitzGerald, CEO of London City Airport, said in a statement. 

The airport’s initial plans for more Saturday flights was rejected last year by local government officials over noise pollution fears, but the previous Conservative government said it would consider an appeal in November.

Green campaigners said the move would likely lead to an increase in carbon emissions, saying any gains in efficiency would be canceled out by having more planes in the sky.

“It’s incredibly disappointing that the new government has failed its first test on climate, and allowed the expansion of this polluting, high-carbon project,” said Alethea Warrington, senior campaigner at climate charity Possible, in an emailed statement.