A large, busy metropolitan city like Mumbai generates approximately 9000 metric tonnes of municipal solid waste (MSW) daily, contributing significantly to greenhouse gas (GHG) emissions. With the current waste management system emitting 998.43 kg CO2 equivalent per tonne, total daily emissions reach about 8,985,870 kg CO2 equivalent. This study uses SimaPro software to analyze the environmental impact of existing waste management practices and assess six alternative scenarios. The most effective strategy combines multiple waste treatment methods: 40% incineration, 25% recycling, 20% composting, and 15% anaerobic digestion. Implementing this approach reduces Greenhouse Gas emissions by 14.2%, lowering daily emissions to 7,708,415 kg CO2 equivalent. This reduction highlights the benefits of integrating diverse waste management techniques to curb pollution. Beyond emissions reduction, sustainable waste management improves air quality, reduces landfill dependency, and enhances resource recovery. By adopting a balanced mix of waste treatment methods, Mumbai can create a more efficient and eco-friendly waste management system. These findings provide valuable insights for policymakers, urban planners, and environmental agencies striving to mitigate the city’s environmental footprint.