London City Airport has been rated carbon neutral by an international agency.
The Docklands based hub announced its ground operations no longer emit the greenhouse gas on Thursday, December 19.
Alison FitzGerald, London City's chief operating officer, said: "[This] is a significant achievement which everyone at [the] airport can be proud of.
"It recognises our efforts to cut carbon emissions in every part of our business - from runway lighting to energy systems - and underlines our commitment to building a more sustainable future."
The Airport Carbon Accreditation programme, which advises airports on how to be more environmentally friendly, has rubber-stamped the neutral status, meaning the airport removes as much carbon dioxide as it puts into the atmosphere.
The greenhouse gas traps heat and warms the planet. London City wants to stop emitting it completely by 2050.
But Ann Basu from campaign group, Fossil Free Newham, argued that carbon neutral status for ground operations "means very little" against the backdrop of the airport's bid to increase flight numbers.
The hub's draft masterplan for 2020-2035 proposes increasing the current annual cap on flight numbers from 111,000 to 151,000 - a 36 per cent rise - to meet forecast growth in passenger demand.
"Flying is by far the most carbon intensive form of travel. Airports need to drastically cut numbers of flights by 2030. Claims of carbon neutrality for airports do nothing to address the climate emergency," Ann said.
John Stewart, of campaign group HACAN East, said: "It is welcome that the operations at the airport are now carbon neutral but the elephant in the sky remains the planes and the CO2 they are emitting."
Extinction Rebellion's Newham branch welcomed the status, but raised concerns about people's quality of life in the surrounding neighbourhoods resulting from carbon emissions.
The airport's biggest airline, British Airways, has already committed to offset carbon emissions on all domestic flights from January.
Professor Charles Egbu, a pro vice-chancellor at the University of East London opposite the airport, said: "We welcome this news and congratulate London City.
"Sustainability is an area that impacts us all and we all need to contribute to this important cause."
As part of its accreditation programme, London City has contacted 48 east London schools to find suitable places to install solar panels to offset its carbon emissions and reduce them in its backyard.
Of the 293 airports in the programme, only 62 have achieved London City's Level 3+ (neutrality) status.
In Europe, there are currently 51 accredited airports in 15 countries. Aside from London City, five other airports in the UK have achieved the same status: Gatwick, Manchester, Stansted, East Midlands and TAG Farnborough.
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