Urban Waste and Pollution

Cities are concentrated producers of waste and pollution. A city of one million people generates approximately 2,000–3,000 tonnes of solid waste per day, along with millions of litres of wastewater and significant quantities of air pollutants. Managing this output sustainably is one of the defining challenges of contemporary urban environments.

Key Definition: The waste management hierarchy ranks waste management strategies from most to least environmentally desirable: Prevention > Reuse > Recycling > Recovery (energy) > Disposal (landfill). It was formalised in the EU Waste Framework Directive (2008) and underpins UK waste policy.

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The Waste Management Hierarchy

graph TD
    A["Prevention<br>(Most preferred)<br>Reduce waste at source"] --> B["Reuse<br>Use items again for<br>same or different purpose"]
    B --> C["Recycling<br>Process waste into<br>new materials"]
    C --> D["Recovery<br>Energy from waste<br>Incineration with energy recovery"]
    D --> E["Disposal<br>(Least preferred)<br>Landfill"]

Prevention

Waste prevention is the most effective strategy but also the most difficult to implement. It requires changes in production processes, packaging design, consumer behaviour, and economic incentives: