The purpose of the light manufacturing district is to provide land for manufacturing and industrial establishments which are clean, quiet and free of hazardous and objectionable elements such as noise, odor, dust, smoke, etc., operate mostly within enclosed structures; and generate little industrial traffic. Heavy manufacturing is permitted as a conditional use. Commercial activities compatible with light manufacturing uses are permitted, other commercial development is prohibited unless introduced under the planned unit development approach. Central water and sewer facilities are required.