UNITED NATIONS, Feb 6 Hundreds of millions of people in South Asia face growing water stress due to over-exploitation, climate change and inadequate cooperation among countries, which are threatening river basins that sustain about half of the region`s 1.5bn people, says a United Nations report released on Friday.

“Fresh water under threat South Asia,” a new report produced by the United Nations Environment Programme (UNEP) and the Asian Institute of Technology examines the state of fresh water resources in selected major river basins in the region, identifies key threats to water resources development and management, and assesses the challenges in coping with these threats.

The three trans-boundary river basins assessed in the report include the largest in South Asia the Ganges-Brahmaputra-Meghna (GBM basin (which spans Bangladesh, Bhutan, China, India and Nepal), the Indus river basin (Afghanistan, China, India, Nepal and Pakistan) and the Helmand river basin (Afghanistan, Iran and Pakistan).

The report calls for urgent policy attention and more research into the impact of climate change on water resources, infrastructure and management practices, as well as improved cooperation among the affected countries and integrated basin management.

UNEP`s executive director Achim Steiner stressed the need to invest in the sustainable management of these river basins.

“These river systems are major economic arteries as well as social and environmental assets for South Asia,” he said. “Investing in sustainable management is thus an investment in the current and future prosperity of Asia and will be a central and determining factor underpinning the transition to a resource efficient, sustainable green economy.”

South Asia is home to one-fourth of the global population, which has access to less than 5 per cent of the planet`s fresh water resources, according to the UNEP report.