When some factory expels byproduct gases from their vents, or dumps liquids to underground water horizons, this is usually considered to be the main pollution source in reality, along with cars & cows. Does this happen with Py mods? It doesn't seem to be, not from looking at pollution map and new pollution statistics tab that is. I searched the forums and for some reason didn't find this suggestion. Also the tailings pond, it says in the description that it pollutes a lot, but I didn't identify any signs of it...
