Create a minimalist vector illustration of an arched underground sewage tunnel. The design should feature smooth walls and a central drainage channel, with emphasis on shadows and lights to create depth and contrast. It incorporates a combination of blue tones in the lighting and shadows, giving a fresh and atmospheric feel to the scene. Include evenly spaced ceiling lights that illuminate certain areas and leave others in darkness, enhancing the tunnel's eerie atmosphere. The overall aesthetic should remain clean and simple, focusing on the interplay of light, shadows and colors.