The bottom four needs in maslow’s structure are referred to as needs.

I believe the answer to this question is "physiological needs".
Physiological needs refer to those that are necessary for survival such as water, food, shelter and procreation. Thank you for your question. Please don't hesitate to ask in your queries. 

Urban growth invariably feeds increased commercialization and industrialization. it requires continually expanding land areas. when urbanization rates are high, and countries do not have the institutional and managerial capacities or economic wherewithal to manage such rapid growths, they exert intense pressure on the types and nature of the resulting settlements. they contribute to the development of overcrowded slums and shanty towns without adequate essential services and necessary infrastructure.-by asit k. biswas and cecilia tortajada