According to a study as part of the Aqueduct project of the World Resources Institute - a non-profit entity headquartered in Washington and funded by foundations, governments, non-governmental organisations and international bodies – these 17 countries, which represent one quarter of the world’s population, use at least 80% of their water reserves each year, with agriculture, industries and municipalities representing the largest source of pressure on water reserves.
Portugal is among the 44 countries that deplete at least 40% of their water reserves, putting themselves in a situation of high risk of water scarcity.
The study’s authors stress that such a narrow margin between supply and demand as that in the most countries under the most water pressure leaves them more vulnerable to variables such as drought or greater demand on reserves, with ever more countries reaching Day Zero – that is, when are left without access to piped water.
The situation is set to worsen unless countries take action, the report warns, citing population growth, socio-economic development and urbanisation as among factors boosting demand, even as climate change makes precipitation more variable.
On the Middle East and North Africa, the world's worst-placed region in this field, the study points out that the reuse of wastewater could represent a new source of drinking water. It notes that 82% of wastewater in those countries is currently not reused.
In India they cite concerns about underground reserves, in addition to those about surface reserves: aquifers are running low, largely due to the use of irrigation. India occupies 13th place on the list of countries facing most water scarcity and its population is three times higher than the combined population of the 17 most pressured countries in the world.
The study also examines regions within countries.
It notes that pressure from lack of water is not a fatality and that reversing the situation depends largely on how resources are managed.
In addition to examples from some countries that have already taken steps to avoid water shortages in taps, such as Australia stemming domestic consumption to avoid a Day Zero, the study presents generic recommendations, applicable in most countries, such as investing in more efficient irrigation techniques and better infrastructure, and treating and reusing wastewater.
The Aqueduct study analysed the situation in 164 countries in all.