Why are our taps running dry?

Chennai, São Paulo, Mexico City, Tehran, Cape Town - these cities have all faced the threat of a ‘Zero Day’, or, having no fresh water left in their taps.

The UN says we’re entering a ‘water bankruptcy’ era, meaning our water ‘current accounts’ are running empty, while our ‘savings accounts’ - the long term stores of water deep underground - have been depleted, with some beyond repair.

So how did we get here?

From clearing forests for cattle grazing, to thirsty AI data centres, Rajan Datar examines the pressures on our global water supply and looks for solutions.

Contributors: Jayshree Vencatesan, Co-founder, Care Earth Trust, India Augusto Getirana, research scientist at NASA's Hydrological Sciences Laboratory, USA Prof Bridget Scanlon, Bureau of Economic Geology, University of Texas, USA Dr Jie-Sheng Tan Soo, Director, Institute for Environment and Sustainability, National University of Singapore

Presenter: Rajan Datar Producer: Phoebe Keane Researcher: Evie Yabsley Editor: Richard Fenton-Smith Technical Producer: Cameron Ward Production Management Assistant: Liam Morrey

(Photo: Indian women with empty plastic pots protest as they demand drinking water. Credit: Arun Sankar/Getty Images)