I am trying to do some cost/benefit analysis for the late game. I am usually in Republic, with 1/3/4 unit support and 2 gpt for each unit above that. Let’s assume I have more units than can be supported, so I am paying the 1 gpt for additional units. By the modern era, I have railed everything and my workers are mostly just used for pollution control. So when I discover ecology and recycling, I am wondering if I should be building mass transit and recycling centers in certain cities. They each cost 2 gpt for maintenance. Does anyone know the probability that a certain city will produce pollution on any given turn? I know certain improvements like factories affect this, but I don’t know by exactly how much. This will allow me to compute the cost of these improvements vs the cost of the workers needed to clean the average amount of pollution.