An international study group has warned that the water shortages in India and other parts of the world will be a serious problem in the days to come.

"Scores of countries are over-pumping aquifers as they struggle to satisfy their growing water needs, including each of the big three grain producers -- China, India, and the United States.

More than half the world's people live in countries where water tables are falling," Lester Brown of the Earth Policy Institute has said.

In India, water shortages are particularly serious simply because the margin between actual food consumption and survival is so precarious.

In a survey of India's water situation, Fred Pearce reported in the New Scientist that the 21 million wells drilled are lowering water tables in most parts of the country.

"In North Gujarat, the water table is falling by 6 meters per year. In Tamil Nadu, a state with more than 62 million people in southern India, wells are going dry almost everywhere and falling water tables have dried up 95 per cent of the wells owned by small farmers, reducing the irrigated area in the state by half over the last decade," Brown has noted.

"As water tables fall, well drillers are using modified oil-drilling technology to reach water, going as deep as 1,000 meters in some locations. In communities where underground water sources have dried up entirely, all agriculture is rain-fed and drinking water is trucked in," Tushaar Shah, who heads the International Water Management Institute's groundwater station in Gujarat, said of India's water situation.

The situation over water is equally serious in Pakistan, whose population is growing by three million a year, and which is also a country that is mining underground water.

"In the Pakistani part of the fertile Punjab plain, the drop in water tables appears to be similar to that in India. Observation wells near the twin cities of Islamabad and Rawalpindi show a fall in the water table between 1982 and 2000 that ranges from one to nearly two meters a year," Brown said.

"In the province of Balochistan, water tables around the capital, Quetta, are falling by 3.5 meters per year.

Richard Garstang, a water expert with the World Wildlife Fund and a participant in a study of Pakistan's water situation, said in 2001 that within 15 years Quetta will run out of water if the current consumption rate continues," he pointed out.

"Pakistan, like Egypt, is essentially a river-based civilization, heavily dependent on the Indus. This river, originating in the Himalayas and flowing westward to the Indian Ocean, not only provides surface water, it also recharges aquifers that supply the irrigation wells dotting the Pakistani countryside. In the face of growing water demand, it too is starting to run dry in its lower reaches.

"Pakistan, with a population projected to reach 305 million by 2050, is in trouble" Brown has warned.