The Regions of Singapore are urban planning subdivisions demarcated by the Urban Redevelopment Authority of Singapore to aid in its planning efforts. Over time, however, other governmental organisations have also adopted the five regions in their administrative work, as for example the Department of Statistics in the census of 2000. The regions are further subdivided into 55 planning areas, which include two water-catchment areas. The largest region in terms of area is the West Region with 201.3 km2 (77.7 sq mi), while the Central Region is the most populous with 939,890 inhabitants in the area in 2015.