Which factors include overcrowding, infrastructure, sewage, water treatment, and societal beliefs?

The factors outlined—overcrowding, infrastructure, sewage, water treatment, and societal beliefs—are best categorized under local factors because they pertain specifically to the characteristics and issues within a particular area or community. Local factors encompass elements that directly affect the living conditions of a population in a specific geographic region.

Overcrowding, for instance, is a phenomenon observed at a community level, influencing resources and quality of life. Similarly, infrastructure pertains to the physical foundational systems (roads, buildings, sanitation) that vary significantly from one location to another. Sewage and water treatment facilities are critical in managing health and environmental standards within a locality, directly impacting the population's well-being.

While societal beliefs could touch on broader societal factors, the context here emphasizes the local community’s specific challenges and characteristics, distinguishing them from wider cultural or environmental contexts. Environmental factors typically refer to natural elements and ecosystems rather than the man-made conditions and socio-economic aspects highlighted by the question.