Zoning laws were designed primarly to

At present, zoning laws regulate those zones which can be used for developing commercial activity or for building residential areas; they also specify the placement, size and height of the structure.

But zoning laws were first designed to protect some districts by means of building walls around these cities. Outside the walls, poor people lived in deplorable and dangerous conditions, while inside this protection it was possible to find civic and religious places as well as the majority of the population.