I remember reading on this forum that it was a good idea to intentionally stagnate growth in cities in which additoinal growth would create unhappy citizens (because those citizens eat food, but contribute nothing, effectivley starving your populace). I just noticed while playing last night that I have been doing the same in terms of health. That is, if a city is 9 Health - 9 Unhealth, I've been stagnating it. Should I not be doing this? What exactly does unhealth do? What is the major risk in having a very very unhealthy city?