GURUGRAM: The quality of groundwater , which accounts for half the water that you get from your taps every day, has worsened enormously over the past year.A response to a right to information (RTI) query from the Central Ground Water Authority (CGWA) revealed levels of elements like fluoride and chloride have increased steeply, in some cases by more than 200%, as have salinity levels. The numbers rang alarm bells among environmental activists, who said this pointed to illegal extraction of groundwater, the depletion of the aquifer because of contraction of recharge zones and contamination from the defunct Bandhwari waste treatment plant continuing unchecked.According to the CGWA, chloride concentration went up to 2,598 mg/litre in 2015-16 from 765 mg/litre in 2014-15 and fluoride concentration rose up to 4.26mg/l compared to 2.10 mg/l in 2014-15. Similarly, nitrate concentration increased from 137 mg/l in 2014-15 to 328 mg/l this year while salinity rose to 6,910 umhos/cm this year from last year’s 3,073 umhos/cm. The permissible limit of fluoride is 1.5 mg/l and chloride is 250 mg/l, while it’s 45 mg/l for nitrates.The RTI application was filed by activist Aseem Takyar.Environmentalists have raised the need to identify areas that have high concentration of contaminants.Sushmita Sengupta, deputy programme manager with the Centre for Science and Environment’s (CSE) water team, said, “While the increase in fluoride and chloride levels could be due to mindless extraction of groundwater, nitrate concentration is a result of waste contamination in groundwater. The solution is to recharge the groundwater so that the level of elements such as fluoride and chloride dissolve easily. For nitrate concentration, steps should be taken after analysis of the sources of contamination.”Vivek Kamboj, an environmental activist, held the defunct waste treatment plant at Bandhwari responsible for groundwater contamination. “Both depletion of groundwater and industrial and waste contamination are the major reasons behind contamination. Leachate from the defunct Bandhwari plant, for instance, has been causing severe damage to groundwater, but authorities are least bothered. We are contaminating a precious resource and we will have to pay the price soon,” he said.Green activist Chetan Agarwal added, “The increase in the maximum nitrate concentration is a matter of concern, as is the increase in maximum salinity. The areas with these high concentrations should be identified and steps need to be taken to contain the contamination sources and also ensure water is treated before use.”Nearly 50% of Gurgaon’s water requirement is met by groundwater — the level of which is currently 33.24 metres. The rest is Yamuna water that comes via canals and through water treatment plants. The city needs 184 million litres of water a day. “This year’s CGWA report shows a noticeable increase in various contaminants and components of groundwater. If compared to last year’s report, there has been an increase of 200% in the level of chloride, while fluoride concentration increased by 100%,” said Takyar.