A by-product of human activity is waste. This becomes a major problem for large cities with no room for disposal sites. Some waste from human activity may be classified as hazardous. Automobiles play a significant role in shaping a modern society. They provide a rapid, safe, and convenient means of moving people and their possessions from one location to another.
Automobiles require natural resources in their construction, use, maintenance, and disposal.
Even electrically powered automobiles have much of their electricity produced by electric generators powered by coal or oil. Many rivers, streams, and aquifers became polluted as industrial waste was discharged into their systems as a means of waste disposal. Today, environmentally sensitive industries consider the reduction of pollution and waste prior to their production. An example of this can be observed in the dry-cleaning industry. The old chemical cleaning process in dry cleaning produced many pollutants.