Urban life is based on amenities. They include sanitation systems and other hygienic services and facilities that range from inside plumbing to public enforcement of hygienic food-handling laws. Essential amenities are: food distribution to a wide number of outlet points; water for drinking, cooking, washing and for commercial and industrial use as well as for fire-fighting and recreation; law enforcement; hospitals and all health services; well-maintaining roadways and pavements; public transportation; parks and recreation areas; and breathable, fresh air. While urban life is based on amenities, its maintenance involves their deterioration and destruction. Natural resources such as city air and water are polluted; sunlight is blocked by high-rise buildings or smog; population pressure destroys parks and recreation facilities, brings excessive automobile and vehicle traffic and engine-exhausts, wears out public transportation equipment, and generally causes the deterioration of every city service including education, law enforcement, and health care.