A greenfield airport is an aviation facility with greenfield project characteristics. The designation reflects certain environmental qualities (using previously undeveloped or empty greenfield land, for example) and commissioning, planning and construction processes that are generally carried out from scratch. While a green field in nature is defined as a wide expanse of natural land (meadow, prairie, grassland), here greenfield denotes that a project lacks any constraints imposed upon it by prior work or existing infrastructure. (A brownfield, on the other hand, remodels or improves upon existing facilities.) Such projects can be highly coveted by engineers as no time must be allotted for demolition of unneeded buildings, etc. constructed in developed areas for the development of the particular place[citation needed]
Modern greenfield airports are under construction in Beijing, Istanbul, Sydney and Chennai. Over the next two decades, the number of airports is expected to increase from 133 to 500. Of these, 367 are slated to be greenfield airports.[1]