Negative CTL region
The negative CTL region was a region in the Bajoran wormhole. The region was located between the positive CTL region and the ring singularity. 

On the chart "The Tunnel in the Sky", which was seen in the schoolroom aboard Deep Space 9 in 2369, the negative CTL region was one of the components labeled on a map of the wormhole. ()

See also
Negative CTL
Regions