As high as mountains climb as deep as oceans dive meaning

That's just another way of saying unbounded. Without limits. What can be as high as a mountain top? Nothing really, you cannot climb higher than a mountain peak. And what can be deeper than the ocean depth? Similarly, you can't dive deeper than the ocean depth. When we talk about mountain peak say of Everest. or ocean depth like say the Mariana's trench; our intellect cannot conceive any parts of the habitable world higher or lower than that. So the idiom means unbounded or without limits.

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