Pollution

Pollution is a byproduct of heat sources. It can only be reduced by building and upgrading Small Parks.

Pollution Money Bonus
All players have a 50% money bonus by default. At 200M pollution (Unconfirmed), a penalty to the money bonus takes affect. Reducing the bonus to 49%. For every 200M pollution, the money bonus is decreased by 1%, until it reaches the minimum of 0%, at 10B pollution.

Trivia

 * The Coal Mine and Oil Pump are the most pollutive buildings in-game, both producing 10 pollution without upgrades.
 * This is accurate to real-life as non-renewable sources such as coal & oil produce the most pollutants, while renewable energy like solar and wind produce none.
 * At 100M pollution, the money bonus is visibly reduced by 1%, however it is a result of the value being rounded, and has no actual affect to the money bonus. (Unconfirmed)