Most Indian cities to go dry by 2020

India is expected to experience a severe water crisis by 2020 with the per capita availability of water projected to be less than 1,000 cubic meters.

Climate change projections showed India's water problems were only likely to worsen and with more rain expected to fall in fewer days and the rapid melting of glaciers, especially in the western Himalayas, India would need to gear up to tackle increasing incidence of droughts and floods, the paper said.

About 1.8 million people died every year as a result of diseases caused by unclean water and poor sanitation, which amounted to around 5,000 deaths a day.

Related: Earth: The parched planet

Earth: The parched planet

But for all its virtues, Chowdhury's 2-hectare farm is sowing the seeds of a global disaster. To grow the fodder that he needs to feed his cows, he is entirely dependent on irrigation water pumped from deep underground. Over the course of a year, his small electric pump sucks twice as much water from beneath his fields as falls on the land as rain. No wonder the water table in the village is 150 metres down and falling by 6 metres a year.

What is less well known is that the success of this "green revolution" was built on a massive investment in irrigation systems. Today the world grows twice as much food as it did a generation ago, but it uses three times as much water to grow it. Two-thirds of all the water abstracted from the environment goes to irrigate crops. This use of water is massively unsustainable, and has led many people to conclude that the apocalypse wasn't averted, only postponed.

The starkest example is India. Over the past decade, the country has seen an extraordinary "barefoot" hydrological revolution. Farmers have hired drilling rigs and bought electric pumps to mine water that has sat undisturbed beneath their fields for millennia. Today, more than 21 million Indian farmers tap underground reserves to water their fields, and two-thirds of India's crops are irrigated with underground water.

The juggernaut is still accelerating. There are a million more pumps every year. We are only just beginning to see the consequences." Shah estimates that at least a quarter of Indian farmers are mining underground water that nature will not replace, and that up to 200 million people face a waterless, foodless future.

The groundwater boom is turning to bust and, for some, the green revolution is over. Fifty years ago in northern Gujarat, bullocks driving leather buckets lifted water from open wells dug to about 10 metres. Now tube wells are sunk to 400 metres, and they still run dry. Half the traditional hand-dug wells and millions of tube wells have dried up across western India. In the southern state of Tamil Nadu, two-thirds of the hand-dug wells have failed already, and only half as much land is irrigated as a decade ago. Whole districts in Tamil Nadu and Gujarat are emptying of people. Suicides among farmers are rife. Many more are joining the millions migrating to urban slums or joining the gangs of construction workers and labourers travelling the roads of India.

His electric pump brings up 12 cubic metres of water an hour. When he needs to irrigate his fields, which he does 24 times a year, it takes 64 hours to pump up all the water he needs. That adds up to 18,000 cubic metres of water a year to grow the fodder to produce just over 9000 litres of milk. That's 2000 litres of water for every litre of milk. According to Shah that is better than the local average.

In the backwoods of Gujarat, I met Haradevsinh Hadeja, a retired Indian police officer who has transformed his home village of Rajsamadhiya by doing just that. He has turned a near-desert landscape of desiccated fields and empty wells into a verdant scene of trees, ponds, full wells and abundant crops. Most of the other villages in the area rely on government water tankers to provide drinking water for much of the year. They have little left to irrigate their crops. That's not the case in Rajsamadhiya. "We haven't had a water tanker come to the village for more than 10 years. We don't need them," Hadeja says.

Microfluidic Device for the Capture and Concentration of Bacteria

Effective detection of bacterial pathogens in large sample volumes is a challenging problem. Pre-concentration routines currently in practice before the actual detection process are cumbersome and hard to automate. An effort is made to address the problem of volume discrepancy between day-to-day samples and the concentrated samples needed for analysis. Principles of conceptual design are used in formulating the ‘Need Statement’, ‘Function Structure’ and in identifying the ‘Critical Design Parameters’ and ‘Design Constraints’. Electrokinetic phenomena are used to exploit the surface charges on bacteria. Electrophoresis is used to transport the bacteria to electrode surface and “Electrostatic trapping” is then used to capture these microbes on the electrode surface. The captured microbes can then be concentrated in a concentrator unit.

A prototype microfluidic device is fabricated for showing the proof of concept. Optimization is done to minimize hydraulic power consumption and wetted volume. Observations from the initial prototype device along with the optimization results are used in building a new prototype device. Operation of this device is demonstrated by capture of bacteria from flow. Qualitative studies are conducted and preliminary quantification is also done.

Biosand Filter Reduces Diarrheal Diseases

University of North Carolina researchers, lead by Mark Sobsey, are the first to scientifically document that filters made of concrete, gravel, and sand can significantly reduce the incidence of diarrheal diseases, the leading cause of death in many third world countries.

Sobsey and researchers in UNC's School of Public Health compared rates of diarrhea and the condition of drinking water in homes in two villages near Bonao, Dominican Republic. They monitored about 150 households without filters for four months, assessing the rate of illness. Then, about half the houses were given biosand filters - concrete containers that hold gravel and sand. All households were monitored for another six months. The team's initial analysis showed the filter reduced diarrheal disease among household members by an estimated 30 percent to 40 percent, including in highly vulnerable young children less than 5 years old. At the end of the study, filters were given to all participating homes.

Can Foreign Ag Firms Help Feed China?

The country's farmers need all the help they can get. Not only have they been deprived of funding and technology, environmental math is against them too. Farmers lack the equipment required to respond to an increasing demand for agricultural products, as well as an adequate social security apparatus.

China's farmers have to feed a fifth of the world's population using 10% of its arable land. Government analysts say per capita water levels, currently one quarter of the global average, will drop below internationally defined crisis levels by 2030 if usage continues at its present rate.

In a nation where agriculture accounts for 70% of water consumption, catastrophe may only be avoided through improved efficiency.

With their years of experience in mechanization, agricultural chemistry and biological research, foreign agri-tech firms are uniquely positioned to capitalize on China's needs. Meanwhile, well- financed overseas food processors and retailers are able to implement large scale infrastructure improvements that are beyond their domestic competitors.