MUMBAI, Feb. 25 -- Mumbai's residents may have to pay a 'user fee' on solid waste management - a garbage tax - to fund the massive process of collecting, transporting and processing the city's trash. The fee proposed to be collected - Rs.687 crore a year from residential properties alone - would help the Brihanmumbai Municipal Corporation (BMC) enhance its waste-management systems, invest in modern technology and improve overall service delivery....