People should have access to around 50 to 100 litres of clean water per day, according to the UN. But this is not always the case, especially in countries with desert areas or affected by droughts.

There’s a technique called fog catching that’s been used on a small scale for decades. Nets are used to trap fog and water is channelled into pipes and storage tanks. But now, in the Atacama Desert in Chile, researchers want to scale it up massively and meet the entire water demand of Alto Hospicio, which is in one of the world's driest regions.

How much water can fog catching provide? And is it clean? The BBC’s Science Correspondent Victoria Gill runs us through how it all works. And we hear from two organisations working on improving access to water across Africa and Latin America.

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