Featured image: People gather around a roadside pipeline to collect drinking water in Bangladesh. Credit: Mamunur Rashid/NurPhoto/Getty

Approximately 4.4 billion people drink unsafe water — double the previous estimate — according to a study published today in Science. The finding, which suggests that more than half of the world’s population is without clean and accessible water, puts a spotlight on gaps in basic health data and raises questions about which estimate better reflects reality.