Why is everyone dead?
Based upon information from online threads and in-game experience it appears that citizens will die at specified intervals based upon when the residential zone was created. There appears to be a few ways to combat this:
- Make sure not to zone in large bursts. Meaning that you should zone a few sections of residential as time goes on and not in one large block while paused.
- Ensure that you have plenty of Crematoriums and Graveyards that can easily access all areas of your residential zones.
Sources: first, second, third, fourth