About 46% of young Cameroonians smoke the substance according to the health ministry - which is typically a mix of tobacco, molasses, glycerine and flavourings.

Doctors say there is a "misconception" that shishas are not as harmful as cigarettes and the British Heart Foundation says an hour-long shisha session can be the equivalent of smoking more than 100 cigarettes.

"Traditionally shisha tobacco contains cigarette tobacco, so like cigarettes it contains nicotine, tar, carbon monoxide and heavy metals, such as arsenic and lead," it says.

In recent years shisha has also been banned in Tanzania as well as Sudan - though the ban there has been reversed and reintroduced several times since.