Environment-filled characters

What does "environment-filled characters" mean?

Context:

Grooms is a social realist who has managed to weave together the art of assemblage and social commentary to poke fun at our human foibles. Like some of his art world predecessors, such as Daumier, Grooms mocks with great affection. His work, like other Pop Art, takes its cues from popular culture, but Grooms is far too theatrical, flamboyant and vaudevillesque to remain true to clean and cool surfaces. Drawing on his interest in movies (and Grooms has made a few movies), many of his pictoramas include sound, light and motion. The range of Grooms’ art environment-filled characters reflects the diversity and dynamism of the wide spectrum of culture, and American urban fare.