1. blue line
2. area around a red-light district where illegal prostitution occurred (marked on police maps by a blue line; 1940s-1956)
3. non-legal public waterway (denoted by a blue line on cadastral maps; sometimes no longer physically existing)
1. area around a red-light district where illegal prostitution occurred (marked on police maps by a blue line; 1940s-1956)
1. area around a red-light district where illegal prostitution occurred (marked on police maps by a blue line; 1940s-1956)
1. If/when the blue line zone; If/when within the blue line zone
1. If it's the blue zone; When it's the blue zone
1. Not in the blue line area.; Not within the designated area.
1. Blue zone; Blue line area
1. Not the blue zone.; Not in the blue zone.
1. It wasn't the blue zone.; It wasn't in the blue zone.
1. Not in the blue zone.; Not within the designated area.
