What's the biggest threat India is facing? It's China's growing need for water. Ask Professor Brahma Chellaney and he puts things in perspective.

When China's demand for water swells, it will ruthlessly pursue its national interest and tap into resources that provide water to India, Kazakhstan, Laos and Cambodia, he says.

China's policy on river waters itself is alarming. It believes in the Doctrine of Absolute Territorial Integrity over river waters. This doctrine calls for absolute control over river waters that originate from its territory, irrespective of what happens downstream, he says.

For example, China has already started building a dam on the Brahmaputra, and is planning many more. "This will affect India, Bangladesh and other neighbouring territories," he says.

Chellaney, who has been a major critic of India's water policy, or more precisely, the lack of it, says the government does not attach water the strategic seriousness it deserves.

The professor of strategic studies at the Center for Policy Research in New Delhi was recently in Mumbai for a meeting organised by the Asia Society Foundation.

The Doctrine of Absolute Territorial Integrity over river waters was a theory propounded by the US first, as the Harmon Doctrine. "This was then picked up by the Russians, and now China... Though the US has abandoned this doctrine, China continues to embrace it," says Chellaney."India, on the other hand, does not understand the value of leverage- based strategy. It gives data without reciprocal benefits. It has almost forgotten the principle of reciprocity," Chellaney says.

China, for instance, has agreements for selling hydrological data. India, he says, provides this data free of cost to Pakistan and Bangladesh, he says."India has to force China to negotiate this and other outstanding issues in exchange for commercial rights. If India does not protect its own interests, why should any other country? Chellaney says.Though India has more fertile land, China has higher productivity. China manages its water resources far more efficiently than India. Its internally renewable water resources are at least 50% higher. But China has a problem. Almost 81% of its water is in South China, with only 19% in North.

The first visible signs of a water crisis are already visible in the Mekong basin, which used to be the breadbasket for Asia (The Mekong basin involves six countries – Cambodia, Yunnan in China, Laos, Vietnam, Thailand and Myanmar). China has six major dams on the Mekong river and three more are proposed. Work on five mega dams on the Salvin (Tibetan plateau) commenced year.

So, what does the future hold? Use of technology for harnessing new sources of power is one interesting possibility, he says. "Already desalination prices have begun tumbling with newer, energy-efficient technologies. I expect more technologies to emerge in this field. And as groundwater resources and rivers dry up because of overexploitation, the advantage will shift from mountains and headwater places to shorelines."