Some of the world's largest and best-known rivers are at risk of drying up as a result of climate change, pollution and bad planning, a report warned today.

The study by the environment group, WWF, focuses on the ten rivers most danger of drying up or dying, and warns that, without action, the world faces "a freshwater emergency".

Five of the 10 rivers listed are in Asia, including the Yangtze, the Ganges and the Salween, highlighting the profound problems facing the region.

Europe's Danube, the African Nile and South America's Rio Grande are among other rivers under serious threat.

Among the problems highlighted in the report - which is published ahead of World Water Day on Thursday - are those caused by dams and dykes, such as those along the Danube. WWF said these have already destroyed 80% of the river basin's wetlands and floodplains.

The extraction of water for agriculture is also taking its toll on rivers around the world, WWF said, with India's Indus river a notable example cited by the study.

Over-extraction can lead to water scarcity and severely threaten freshwater fish populations, which serve as an important food source for tens of millions of people worldwide.

The report, which draws on eight international assessment reports, offers solutions for the problems caused to rivers by over-extraction, pollution, over-fishing, climate change, dams and invasive species.

It calls on governments to better protect rivers and ensure more sustainable water use in order to protect people's livelihoods and the habitat provided by freshwater sources.

"The world is facing a massive freshwater crisis, which has the potential to be every bit as devastating as climate change," said Dr David Tickner, head of WWF UK's Freshwater programme.

""We need business leaders and government to recognise that climate change is not the only urgent environmental issue that needs to be dealt with, and that they need to take notice of this freshwater emergency and act now, not later."

Dr Tickner said businesses, particularly those relying on food and fibre products that demanded a lot of water to produce, should look at how they could be more water efficient.

"Conservation of rivers and wetlands and security of water flows must be seen as part and parcel of national security, health and economic success," he said.

"Emphasis must be given to exploring ways of using water for crops and products that do not use more water than necessary."

To ensure a worldwide response to the problem, WWF said there should be agreements between countries as to how to manage water resources.

Dr Tickner added: "The freshwater crisis is bigger than the ten rivers listed in this report but it mirrors the extent to which unabated development is jeopardising nature's ability to meet our growing demands."