Here's why:
* The characters: The characters, particularly Slam, have a vernacular and slang that's indicative of an urban setting.
* The themes: The themes of poverty, gang violence, and limited opportunities for young people are often associated with urban environments.
* The social context: The book addresses social issues like the penal system, racial discrimination, and the impact of poverty, all of which are prominent in urban centers.
While a specific city isn't named, the overall atmosphere and references suggest an environment similar to New York City, Chicago, or Philadelphia. The novel doesn't focus on a specific location, rather it uses the urban setting to explore universal themes of youth, identity, and social justice.