Mumbai, March 19 -- A section of the underground tunnel of the Aqua Line (Metro Line 3) was damaged on March 5 after an unauthorised borewell drilling operation near Metro Cinema in south Mumbai, prompting police action days later. Metro Line 3 currently serves around 1.8 lakh passengers daily, including nearly 60,000 commuters between Cuffe Parade and CSMT. According to the Mumbai Metro Rail Corporation (MMRC), the breach occurred when Shree Chandrama Water Supply Company was drilling a borewell without obtaining mandatory permission from the authority. The drill is believed to have pierced part of the tunnel, located about 18 metres below ground near the Chhatrapati Shivaji Maharaj Terminus (CSMT) metro station. The minor damage was later detected during a routine inspection by a metro surveillance team. Despite the breach, train services between Cuffe Parade and Jogeshwari-Vikhroli Link Road continued without disruption. MMRC officials then approached the Azad Maidan police, who registered an FIR on March 13 against the company's proprietor, Ram Babu Rai, for allegedly endangering public safety and damaging metro infrastructure. "We have registered a case against the proprietor for unauthorised drilling carried out on March 5. The offence was registered on March 13 after due verification," said a police officer. The accused has been booked under relevant sections of the Bhartiya Nyaya Sanhita and the Metro Railway Act. No arrests have been made so far, the officer said. Officials reiterated that any excavation or construction within a 50-metre radius of metro infrastructure requires prior approval from MMRC - a norm that was allegedly violated in this case. A spot inspection (panchanama) was conducted by police during non-operational hours....