 The town is entirely surrounded by Green Belt land, a land designation which originated in London to prevent the city sprawling, and 21% of the district is allocated as Green Belt.The National Planning Policy Framework states that one of the purposes of Green Belt land is to protect unrestricted sprawl from large built-up areas.Harlow Town Park, at a size of 71.6-hectares (just under 1 km²), is one of the largest urban parks in the country.