World Health Organization figures show that Egypt ranks high among lower middle-income countries in terms of the number of deaths related to water pollution.

The UN estimates critical shortages in the country by 2025.

• 'My wife doesn't shower any more'
• Drought forces Rome to cut water pressure

5. Jakarta

Like many coastal cities, the Indonesian capital faces the threat of rising sea levels.

But in Jakarta the problem has been made worse by direct human action. Because less than half of the city's 10 million residents have access to piped water, illegal digging of wells is rife. This practice is draining the underground aquifers, almost literally deflating them.

As a consequence, about 40% of Jakarta now lies below sea level, according to World Bank estimates.

To make things worse, aquifers are not being replenished despite heavy rain because the prevalence of concrete and asphalt means that open fields cannot absorb rainfall.

6. Moscow

One-quarter of the world's fresh water reserves are in Russia, but the country is plagued by pollution problems caused by the industrial legacy of the Soviet era.

That is specifically worrying for Moscow, where the water supply is 70% dependent on surface water.

Official regulatory bodies admit that 35% to 60% of total drinking water reserves in Russia do not meet sanitary standards

• Somalia drought claims dozens of lives
• Raw waste water use on farms '50% higher'

7. Istanbul

According to official Turkish government figures, the country is technically in a situation of a water stress, since the per capita supply fell below 1,700 cubic metres in 2016.

Local experts have warned that the situation could worsen to water scarcity by 2030.

In recent years, heavily populated areas like Istanbul (14 million inhabitants) have begun to experience shortages in the drier months.

The city's reservoir levels declined to less than 30 percent of capacity at the beginning of 2014.