The colonial 1948 Master Plan for Nairobi still acts as the governing mechanism when it comes to making decisions related to urban planning. The Master Plan at the time, which was designed for 250,000 people, allocated 28% of Nairobi's land to public space, but because of rapid population growth, much of the vitality of public spaces within the city are increasingly threatened. City Park, the only natural park in Nairobi, for example, was originally , but has since lost approximately of land to private development through squatting and illegal alienation which began in the 1980s.