Mumbai, Sept. 22 -- As part of plans to augment water supply to Mumbai, the state government on Monday approved an eight-kilometre-long water tunnel between Pise and Panjrapur in Thane district. The tunnel will replace four pipelines that ferry water from the pumping station at Pise till the water treatment plant at Panjrapur, and it will be designed and constructed by the Brihanmumbai Municipal Corporation (BMC) at its own expense without placing any financial burden on the state government, according to the government resolution issued by the urban development department on Monday. Pise and Panjrapur, located in Bhiwandi in Thane district, comprise the Pise-Panjrapur Complex (PPC), a major water treatment facility run by the BMC. A pumping station at Pise lifts raw water directly from the Bhatsa river, while the water treatment plant at Panjrapur purifies the water before it is piped to Mumbai and its suburbs. At present, water is transported between Pise and Panjrapur via four pipelines spanning 8 kilometres. Three pipelines have a diameter of 2,235 mm each and were commissioned between 1979 and 1996, while the fourth pipeline with a diameter of 3,000 mm was commissioned in 2007. Given the rising water needs of Mumbai and lack of space next to the existing pipelines, the BMC had sent a proposal to the urban development department in March 2026, seeking permission to construct a water tunnel between the two facilities. The government resolution issued on Monday said that permission had been granted subject to conditions, such as the project not creating any financial liability for the state government, and the BMC ensuring that buildings and other structures along the route are not damaged during excavation. The BMC will also have to check whether approvals are required from the ministry of environment, forests and climate change and the Groundwater Survey and Development Agency, and secure the necessary clearances. The state government has directed the BMC to select a tunnel boring machine (TBM) only after conducting a detailed geological study of the underground soil and rock along the proposed route. The civic body will have to take necessary precautions to prevent any disaster during or after construction, particularly because of heavy rainfall during the monsoon. It will also have to properly dispose of construction waste and take steps to control dust pollution. Silencers, sound barriers, rubber mats for trucks carrying excavated material and hydraulic crane systems will have to be used wherever necessary, and noise levels during excavation must be below 55 decibels, the GR said....