From the book "Rome on 640K a Day":

Each city has a "tolerance" for 20 Smokestack Points per turn. Each point generated beyond that become a smokestack on the city display, representing a 1% chance per turn that a square around the city will become polluted.

  • Smokestack Points = Industrial Pollution + Pop. Pollution

  • Industrial Pollution = # of shields generated by city.
  • Divide by 2 if city has hydro or nuclear Plant; OR
  • Divide by 3 if city has a Recycling Center.

  • Population Pollution = City Size * Pollution Modifier.

    • Pollution Modifiers = 0.25 with Industrialization;
      • 0.50 with Automobile;
      • 0.75 with Mass Production;
      • 1.00 with Plastics;
      • 0.00 with Mass Transit.
    • Note: Mass Transit eliminates Population Pollution.

City PollutionEdit

Pollution city screen (Civ1)

Pollution may be caused by large resource production in cities, large city populations, nuclear weapons, or the meltdown of a Nuclear Power Plant. If a city has a potential pollution problem, smokestacks in the city display information window indicate the probability that a nearby map square may become polluted.

Map PollutionEdit

Pollution map (Civ1)

The pollution in a map square may be cleaned up by a Settler. Move the Settler into the square and press the Pollution key (P key) or choose the Pollution option from the Orders menu. It takes four turns of work to clean up pollution. If pollution gets out of control, Global warming may occur.