HYDERABAD: New research has shown that the largest groundwater depletion in the world is happening in northern India. Delhi is the epicentre of this fast-developing crisis, and it’s getting worse by the day.“From Delhi, Haryana, Punjab, Western UP and Rajasthan, 32 cubic km of water is being lost every year, which is much more than the usual, and it’s only partially being recovered in successive monsoons,” said Dr Virendra M Tiwari, director of National Geophysical Research Institute (NGRI), which conducted the research. In summers, the strain on underground aquifers is higher. “In a drought year, the extraction in northern India is going up to 100 cubic km,” he said.Scientists say that groundwater is being pumped out 70% faster than what the Central Groundwater Board of India estimated earlier. Some reports say around 172 cubic km of water was pumped out in the 1990s every year. “We have no clue how much ground water storage is left in the region. But what we clearly know is that the picture is very grim,” said Tiwari in an interview to STOI.With the surge in population and shrinking of surface water resources, the level of water in underground aquifers in the region is falling by over 10 cm per year, research has shown. “And yes, Delhi is the centre of that with several other environmental impacts. Nutrients are dying out, soil type is going bad. It has a huge cascading effect,” Tiwari said.The report comes close on the heels of a Niti Aayog report last year that predicted that Delhi, along with several other metros, could run out of groundwater by 2020. According to NGRI estimates, Delhi requires 1 cubic km of water every year for drinking, industrial and domestic purposes.The top NGRI scientist also feared that drying up of the Indo-Gangetic basin, comprising some 2,000 km of land from Pakistan to Bangladesh, may also trigger moderate earthquakes. Drying up of groundwater by using bigger pumps from deeper borewells is also causing largescale contamination of water.While 10 years ago, arsenic-contaminated water was largely seen in some parts of West Bengal and Bihar, it’s now being seen moving in a northwest direction. The Ganga basin region has two big aquifers. While one is the upper aquifer, which has already shown arsenic contamination, the lower aquifer is free from it. But people have started to overexploit both, leading to more cross contamination, scientists say.Multiple studies by research agencies have shown how paddy is getting infected with arsenic, and there are fears that it will affect other crops and have a disastrous impact on health. “All the groundwater pumping is happening for agriculture and perhaps cannot be stopped. So now, you have to find a way to manage sustainable water,” Tiwari says.Worried over the state of groundwater in India, the government has entrusted NGRI to look for new aquifers in the country. Scientists here have used helicopter-borne electro-magnetic tools to find new fractures zones beneath the earth, containing untapped water in cities like Surat, Nagpur, Tumkur in Karnataka, among other areas.“We have found new aquifers and now we have to upscale our work in those areas and ensure proper water management methods are followed while drawing water,” Tiwari added. A huge success for NGRI has been in Surat, where Tiwari says they could locate new source of groundwater for the city using heli-borne technology.