Preeeeety sure those smoke stacks are one of the new engineering projects.
What i think those project do: change the source of energy in a city. i.e. if you build the "burn coal" project, all power plants within a city (or the one in the industrial zone) change into a coal-burning power plant. and if you build the solar power project the power plants turn into solar power plants. and so on...
What i think those project do: change the source of energy in a city. i.e. if you build the "burn coal" project, all power plants within a city (or the one in the industrial zone) change into a coal-burning power plant. and if you build the solar power project the power plants turn into solar power plants. and so on...