Mumbai: The state revenue department recently ordered that a criminal complaint be lodged with the economic offences wing (EOW) over alleged illegal commercial extraction of groundwater from three sites in south Mumbai and its sale through tanker operations.In a May 21 communication, the deputy collector’s office directed a naib tehsildar to approach the EOW and record a formal statement regarding complaints of unauthorised extraction in Kalbadevi, including Popatwadi and Jambhulwadi.The directive came after a series of complaints and RTI applications filed by groundwater activist Sureshkumar Dhoka, who alleged widespread violations of groundwater regulations and commercial tanker operations without mandatory approvals.It also came during a 10% water cut in Mumbai amid concerns over monsoon inflows. BMC officials have stepped up monitoring of water-filling points and tanker movements to ensure equitable distribution and prevent supply distortions.Documents reviewed by TOI suggest that the issue extends far beyond a few locations. Communications exchanged among BMC, district authorities and groundwater regulators reveal a fragmented regulatory framework in which multiple agencies share responsibility, but none maintains comprehensive oversight of commercial groundwater extraction.Among the most significant disclosures is the scale of groundwater infrastructure in the city. BMC records shared with district authorities indicate the existence of 17,457 registered wells, including borewells, ring wells and surface wells, across Mumbai and its suburbs, but only 619 NoCs by Central Ground Water Authority (CGWA) and related permissions have been disclosed. Civic authorities have identified 385 locations allegedly linked to groundwater extraction and tanker-filling activities and referred them to district officials for action.Joint inspections by BMC and Central Groundwater Board found that on average, water to fill around 10 tankers—nearly 1 lakh litres—was being extracted daily from each inspected well. Dhoka claimed the actual extraction may be higher.Official correspondence also shows BMC’s insecticide department stating that its permissions are limited to public health and non-potable use of wells and that it lacks powers to regulate commercial groundwater extraction or recover environmental compensation.Groundwater Surveys and Development Agency, established by the state govt, has told authorities it does not maintain consolidated data on commercial groundwater extraction in Mumbai because such permissions fall under CGWA. Yet, Mumbai’s groundwater assessment units continue to be classified as “safe”.