There is a tendency to utilize underground space for the less ornamental purposes of civilization; there is the Metropolitan Railway in London, for instance, there are new electric railways, there are subways, there are underground workrooms and restaurants, and they increase and multiply.
Polystyrene can be naturally transparent, but can be colored with colorants. Uses include protective packaging (such as packing peanuts and CD and DVD cases), containers (such as clamshells), lids, bottles, trays, tumblers, and disposable cutlery.
Polyvinyl Chloride is a widely-used plastic. PVC containers offer clarity, durability and chemical resistance. They are primarily used for household goods such as soaps and cleaners, chemicals and personal care items. The material is often used for pipelines in the water and sewer industries because of its inexpensive nature and flexibility.