What systems are essential for proper sewage and waste removal in urban areas?

Sanitation is crucial for effective sewage and waste removal in urban environments because it encompasses a range of services and infrastructure specifically designed to manage human waste and refuse. Proper sanitation systems, including sewage treatment plants, drainage systems, and waste collection services, help prevent the spread of diseases, protect public health, and maintain overall hygiene standards in densely populated areas.

In urban settings, where the population density is high, the volume of waste produced is significant, making an efficient sanitation system indispensable. It ensures that waste is safely disposed of, treated, or recycled, thereby contributing to a cleaner and more livable urban environment.

The other options, while they may be important in their own contexts, do not directly relate to sewage and waste removal. Public transport primarily focuses on the movement of people, traffic congestion pertains to transportation efficiency, and squatter settlements refer to informal housing which may lack proper sanitation facilities in the first place. Thus, sanitation stands out as the key system for managing waste effectively in urban areas.