Which job might be held by someone in a mid-level caste?

The caste which can be considered a mid-level caste is the Vaishya  and the most common occupation of the Vaishya would be agriculture and animal rearing. The case lower to Vaishya would be occupied in service of the other castes.

So you know what happened and so it doesn’t repeat it’s self

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