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The Search for Pure Water
What鈥檚 the best way to find clean water? Toby Murcott from the 大象传媒 Science Unit claims rain is the purest natural source of water, despite increasing impurities as a result of pollution and acid rain.
Also on the programme: who are spin doctors, what do they do and why do politicians use them?
大象传媒 World Service Archive
This programme was restored as part of the World Service archive project
