NEW DELHI: As water trains and tankers help battle Latur's worst drought ever, rampant extraction of groundwater could soon push Delhi, Punjab, Haryana and Rajasthan towards a similar harrowing shortage of water.Analysis of water use by different states shows that a gradual decline in per capita availability could leave these states in the same precarious position as the Marathwada region of Maharashtra, which has faced two consecutive years of drought.The latest assessment of the country's dynamic groundwater resources, performed by Central Ground Water Board (CGWB), shows that these states, in fact, consume much more groundwater than their rechargeable limit every year, making them vulnerable to severe water scarcity.Delhi recently witnessed how perilous the situation can get when agitating Jats cut off its water supply from Haryana. It could get much worse in the future if one looks at the way Delhi, Haryana, Punjab and Rajasthan have been drawing water from the ground.Referring to the situation in Punjab and Haryana, former CGWB scientist Shashank Shekhar said, "Indiscriminate use of water in agriculture is a major concern. The practice of providing free electricity to farmers must be immediately discontinued to stop the misuse of groundwater in Punjab.""Since agriculture consumes the maximum water across the country, the use of drip irrigation and sprinklers must be encouraged through various incentives," he added.Though the record of Maharashtra is better than its northern counterparts in terms of groundwater extraction, Latur district had been extracting more than the state average and now it does not have water to draw from existing borewells."There is need to drill a number of borewells in Latur with the help of geological data and remote sensing maps on prevailing hydrological information," said Shekhar, currently an assistant professor in Delhi University's geology department. "Many of them may fail to trace water. But there are chances that a few of them will tap the water bearing rocks," he added.Though the exact estimate of groundwater resources can only be made after completion of the ongoing exercise of aquifer (underground layer of water-bearing rock) mapping, the Centre is, meanwhile, looking at various options to conserve water in a big way. One option is to introduce the tank-based water conservation model practised by the 11th century Kakatiya dynasty in Warangal area.Under the Kakatiya dynasty, the then kings had promoted a small tank-based irrigation system which turned out to be a prudent method. Inter-connected rain-fed tanks were built to store rainwater. The Telangana government has, in fact, already launched 'Mission Kakatiya' that aims to de-silt the existing tanks and build more such tanks to conserve water.