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.
Also, recycled polystyrene cannot in most cases be used for products that contact food because of health concerns, even though the material is usually sterilized by the recycling process. Recycled EPS might be used instead to create packaging or other materials, but new EPS is always needed for coffee cups and plates.