Cape Town might be the first major city to run out of drinking water, but it is just one of a growing list of cities that are dealing with the same threat. Beijing, London, Moscow, Mexico City, and Miami are also at risk of running out of drinking water, with reasons varying from contamination to reserve depletion to leakage. Worse still, around half of the world’s population has to deal with water scarcity during at least part of the year, including residents of a quarter of the world’s largest cities. Using data from the BBC and the World Health Organization, Jo Di Graphics created a map that shows which countries have access to basic drinking water services and which of the biggest cities are running out of water.

According to WHO, “basic drinking water services” means that drinking water is a) accessible on premises, b) available when needed, and c) free from contamination.