Most industries produce waste products which can be difficult or dangerous to dispose of. Coal and oil fired power stations produce enormous amounts of waste. A large coal power station will send 17 million
tons of flue gas out of its chimney each year.
The amount of garbage produced each day is growing at an alarming rate. Many big cities all over the world face a crisis because they are running out of space to dump wastes. One of the solutions to this problem is recycling, that is, reusing materials.