I was in the process of expanding my city when the waste management "unlock" appeared. I progressed a few days' time and checked my housing to see if conditions were deteriorating because of waste but it seemed nothing was happening (this is my first save where I've unlocked waste management). I went back to designing a new plot system for large housing, which I unlocked shortly after waste management, but suddenly my income dropped to negative 2 billion per day. Obviously I was completely unable to recover from this and so had to revert to an earlier save.
Is this a bug or did is this just how the game tells me I lost?