Large parts of the island city and a few suburbs would face a 25 per cent water cut for 24 hours starting 10 am Saturday. The cut is to facilitate connecting of water mains (pipelines) as part of the Maroshi-Vakola-Mahim-Ruparel underground tunnel project in Bandra east. The cross connection between the tunnel and the 600-mm main will help improve water distribution in parts of south Mumbai and western suburbs. The expenditure to build the 12-km-long tunnel,one of five underground ones planned by BMC to prevent encroachment on water mains,contamination and theft,is about Rs 300 crore. Areas that will face the cut include wards A,C,D,G-North,G-South and H-West (Dongri,Malabar Hill,Dadar,Sion and Matunga),Bandra(w),Khar(w) and Santacruz(w).