Environmental London – the facts

Scattered with more than 3,000 parks and open spaces, London is one of the greenest capitals in the world. But it has some way to go before it can be hailed the cleanest.

• - An estimated 20 percent of London's land area is under tree cover, with 500,000 trees on the city’s streets alone. An average of 75,000 new trees are planted each year.
• - London has around 1,500 sites of Importance for Nature Conservation, aimed at protecting wildlife habitats and species, covering some 30,000 hectares (74,000 acres). With the iconic River Thames pumping through its heart, around two thirds of the city is either green space or water.
• - Some 5,000 acres (2,000 hectares) of the green environment lies within eight Royal Parks - including the famous Hyde Park - which are owned by the royal family, but free for all to access.
• - Foxes have been sighted in every London borough in the last five years, with estimates suggesting around 10,000 red foxes may be roaming the capital. There are also signs of wild deer moving in.
• - Air pollution causes more than 4,000 premature deaths a year in London, scientists have estimated. The capital has been in breach of EU air quality laws since they came into force in 2005. London's air quality is ranking among the worst in Europe.
• - In 1858 the stench from the Thames was so potent that parliament was forced to stop work.
• - Today the river is massively improved - even harbouring seahorses and 125 species of fish - but nevertheless millions of cubic metres of untreated sewage pour into it each year.
• - In a typical year, around 39 million cubic metres (1.37 billion cubic feet) of untreated sewage discharges into the River Thames.