Such utopian project and company town's in fact evaded the problem created by the continual growth of industrial cities. It had been recognized already in the seventeenth century that greenery could help to puriry polluted air , hence the introduction of squares planted with trees and shrubberies which became a conspiuous feature of property development in london and which were to be included and other colonial cities in america. London also had the benefit of vast royal parks, often called 'the lungs of the city' and most European capitals also had royal parks partly open to the public