Iraq is facing a water crisis.

Last summer the city of Basra fell sick. More than 100,000 people were rushed to hospital after being poisoned by the city’s water supply.

Around the same time, the country’s marshes – believed to be the original Garden of Eden – shrunk to a quarter of their original size.

In northern Iraq "waterkeeper" Nabil Musa is fighting to protect the environment.

He showed BBC News's Martin Patience why the country was facing what he called its gravest threat yet.

Camera: David Bull. Producer: Firle Davies.