Achieving a color banding effect?

Essentially what i want to do is reduce the smoothness of the lighting in a level, similar to the image below…

231488-colour-banding.png

Could someone point me in the direction of a post process or something that will do this?
Thanks.

below i will link a unreal training live stream where they accomplished this same thing. basically you want to look into the cel shaded tutorials out there.

That’s perfect! Thank you so much.