Wow. This is starting to get complex is it not? Any way to completely screw-up your country by mistake in this game?
It can all come to a screeching halt if the transport system isn’t right - if a train gets stuck and then holds up other trains - no one is going to work, nothing gets produced for a while and the nines are empty and the subsequent industries dependant in those resources - you do get a ‘this train is stuck’ notice but not immediately
The other thing I guess is not keeping citizens happy - they will ‘escape’ if their happiness is too low - I’ve had a block of flats just out of range of the local store and everyone there with no access to food or meat but again the game does a good job of telling you citizens are unhappy