High-altitude thirst

CHINA is so vast, it quickly becomes the largest market for almost anything it consumes. Such is the case with bottled water. Chinese drink 40 billion litres (70 billion pints) of the stuff each year, up over 13-fold since 1998. That growth has a long way to go if China ever consumes as much per person as Mexico (see chart). But finding clean supplies is difficult; rivers, lakes and even groundwater in China are often foul. Hence the huge demand for a seemingly inexhaustible source of pristine water that is cheap to extract, sells at a premium and can now, thanks to massive investment in infrastructure, be taken to coastal cities: Tibetan glaciers.