Recent trajectories of production and consumption patterns have resulted in massively rising quantities of municipal solid waste (MSW). Building on the Shared Socioeconomic Pathways, we build two sets of global scenarios until 2050, namely baseline and mitigation scenarios. We assess trajectories of future MSW generation and the impact of MSW management strategies on methane and air pollutant emissions. In 2050, the adoption of mitigation strategies in the sustainability-oriented scenario yields earlier, and major, co-benefits compared to scenarios in which inequalities are reduced but that are focused solely on technical solutions. In 2050, the GHG emissions in the sustainability-oriented scenario amount to 182 Gg CO2eq/yr of CH4, to be released while particulate matter, and air pollutants from open burning of MSW can be virtually eliminated. We demonstrate that the 6.3 target of the SDG 6 can only be achieved through more ambitious sustainability-oriented scenarios that limit MSW generation and improve management.