Tory hopeful Zac Goldsmith has promised to make the capital "the greenest city on Earth" if elected while Labour rival Sadiq Khan hopes to be "the greenest mayor London's ever had". Both candidates have promised to pedestrianise the shockingly polluted Oxford Street, protect the green belt and make London a National Park City, ensuring green space is accessible for all residents.
In his Living Environment manifesto (PDF), launched 11 March, Goldsmith outlined a series of aims as part of a commitment to having a "zero-carbon London" by 2050. Many of them echoed promises made by Labour hopeful Sadiq Khan when he released his manifesto just days earlier.
Goldsmith said he would give a "Green Space Guarantee" if elected on 5 May, promising all Londoners would live within 10 minutes' walk of a green space – whether a park, common or wood - by 2020. Two million residents currently live further than 1km from an open green space, according to an IPPR survey from 2015.
Two central planks of Goldsmith's policy are reducing air pollution and cooling the city. Pollution would be mitigated by "an ambitious programme of tree planting, green roofing and green walling" while public realm interventions, including public fountains, green roofs, tree planting and reflective surfaces such as solar panels would help with the heat island effect.
This would lead to "a city that is healthier and more pleasant to live in, reduced summer illness and deaths, reduced burden on the NHS due to lower heat impacts on health, reduced demand for air conditioning and electricity, and improved air quality".
Goldsmith said London should follow the lead of Amsterdam, where silver birch, grape vines and fruit trees are being planted to improve the air.
He also promised to double the number of park police, adding 80 extra police community support officers who would keep parks clean and combat wildlife crime. Their efforts would be focused on the eight Royal Parks.
Communities would also be given the right to adopt council green space, turning them into allotments or gardens with the help of grants of up to £5,000. The legacy of Boris Johnson's pocket park programme would continue, with 200 pocket parks planted around the capital and 100 new pocket farms at primary schools.
He also promised to make sure the public can access new public green space created by developers as a result of a planning obligation, through an "Urban Right to Roam", rather than letting it be fenced off.
Goldsmith commented: "As someone who grew up near Richmond Park, I feel strongly that everyone in our city should have somewhere they can go to escape the frantic pace of urban life. My plans will ensure every Londoner has access to green space."
Goldsmith released his manifesto days after Labour's Sadiq Khan. Khan, who is leading the polls, said in 2015 he hoped to be "the greenest mayor London's ever had". His plans include planting 2m trees across the city in his first term, with a particular focus on schools and colleges. He would also improve the city's public realm, creating more "liveable" streets and public spaces across the city.
He said: "I am passionate about the amazing green spaces and views – commons, parks, heaths, playing fields and waterways – that do so much to make London a fantastic place to live. It is on these green spaces that our city's biodiversity and wildlife is most concentrated, our children play and learn about nature, and where we Londoners go to relax. With huge pressures on land for housing and other uses, it is essential that we maintain these spaces, and even expand upon them."
Khan said he would strengthen protections for open spaces within the London Plan, including playing fields, Metropolitan Open Land, and Sites of Importance for Local Nature Conservation and nature reserves.
He also said he would protect wildlife and biodiversity by creating green corridors through the city, and ensure that the Met's Wildlife Crime Unit is properly resourced.