Northwest India is fast running out of groundwater. As much of the world faces growing water scarcity, will mass migration and water conflicts become inevitable? Do we take water for granted at our peril? Presenter Justin Rowlatt hears from chemistry professor Andrea Sella of University College London why water is essential for life, and why it is far weirder than we realise. Laurence Knight reports from a parched Rajasthan on what can be done to stop farmers there from pumping the ground dry. And water expert Claudia Ringler of the International Food Policy Research Institute discusses how bad things could get.

(Picture: Man walks across bed of a dried-out lake in Ahmedabad, India; Credit: Sam Panthaky/Getty Images)