Household affordability of sanitary landfilling is governed by cost allocation rather than metropolitan economic capacity

Open dumping remains a dominant municipal solid waste disposal practice globally, including in megacities whose populations and economic output rival that of small countries. Sanitary landfilling is a common transition away from open dumping, yet system-level feasibility does not translate into household affordability. Here we quantify this divergence using an integrated city-scale framework that combines spatial landfill siting, engineering-based net-present-value modeling, and satellite-derived metropolitan gross domestic product. Applying this framework across six developing megacities with over 100 million residents, we find that all cities possess surplus land meeting screening-level suitability criteria. Required cost-recovery tipping fees range from 54–130 US dollars per tonne, with 5 th –95 th -percentile intervals of ±25%–30% under joint parameter uncertainty. Under full household cost recovery, these fees imply annual disposal costs equivalent to 1.2%–2.0% of the minimum wage, whereas associated revenue requirements represent only 0.26%–1.04% of metropolitan gross domestic product. Across cities, household affordability is uncorrelated with metropolitan economic capacity. Landfill depth is the dominant engineering control on affordability, particularly in high-rainfall systems, but cost allocation exerts greater leverage than any design parameter. Thus, technically and macroscopically feasible landfills may remain difficult to sustain through direct household cost recovery without cross-subsidization and public financing.