Why is the area that should be dark getting brighter?

[gallerykim]

I created a fairly long tunnel using boxes in a new level and blocked the entrance. The inside gets darker, as shown in the picture, but at some point, it starts getting brighter again.

How can I make the inside darker?

[ClockworkOcean]

Try tuning off fog

[gallerykim]

I can’t turn off fog because I want to use volumetric fog for lighting

[glitchered]

you could create a controller blueprint with some trigger boxes inside the tunnel. dim the fog or change the color.

[ClockworkOcean]

But that does it, right?