A Dupont engineer created polyethylene terephthalate (PET) bottles in 1973 and the single-use containers have become cheaper than the contents.
There has been a steady decline in the use of glass, which is heavier and more expensive to make, but can be easily cleaned and reused.
Just 30 years ago many people did not buy water, which is free from the tap. Bottled water is perceived as cheap and, combined with the medical message to keep hydrated, has become ubiquitous.