India, densely populated and overwhelmingly agricultural, faces a serious water shortage as a growing population, less reliable monsoon rainfall, and the demands of industrialisation combine to deplete an already-scarce resource.

A recent report by McKinsey and Company found that by 2030, India's demand for water would be more than double its supply.

Already, many of India's most famous rivers, such as the Ganges and Yamuna, are toxically polluted, and major cities often run dry of drinking water.

The Australian government's eWater agency has signed a memorandum of understanding to share its hydrological modelling platform Source with the Indian Institute of Technology.

Australia developed the Source software over 15 years, at a cost of more than $300 million, as a modelling tool to improve the management of Australia's major river system, the Murray-Darling Basin.

In Delhi, eWater chief executive Gary Jones said there were similarities in India's river basins to the Murray-Darling experience, including competing demands for water from different sectors, conflict between states over water rights, high rainfall variability, and the effects of climate change.

''All of these things, in Australia and in India, present great challenges for you, if you're trying to sustain and manage your water resource, trying to grow your economy, trying to grow food for your people, trying to get your industries up and running, trying to provide water for mining, trying to look after the environment,'' Professor Jones said.

But there were differences too, Ashvin Gosain, who will head the institute's Source program, said.

India has a couple of cities - Mumbai and greater Delhi - as populous as the entire Australian continent.

''And the ground realities can be totally different. In the case of Australia, you talk of a farmer who has about 1500 hectares; here a farmer might have half a hectare. Their problems are different.''

Mechanisms like a water price, which has been used successfully in the Murray-Darling to return water to the environment, might not work in India, ''because you would exclude those who need water but simply cannot afford it''.

Source, Professor Gosain said, would allow models for India's future water use and needs to be built, to determine where water should be allocated.

About 600,000 Indian children die each year largely because of inadequate water supply and poor sanitation, according to UNICEF.

Half the water in rural India is regularly contaminated with toxic bacteria and city supplies are precarious.

India's National Geophysical Research Institute found that, on current usage, ground water supplies in Hyderabad would run dry in three years, and in Delhi within five years.