Why environmental costs fail to deter migration: survival pressure and asymmetric externalities in Mongolia

Cities in the Global South face continuing rural-urban migration that proves resistant to policy intervention. Mongolia's capital Ulaanbaatar (UB) exemplifies this: migration has persisted through periods of active policy restriction, worsening infrastructure strain, and severe air pollution. This study investigates why such migration persists through a mixed-methods approach combining SWOT analysis, k-means clustering, and satellite-based land cover change assessment. Our analysis reveals a statistical separation between privatized benefits and socialized costs, a phenomenon we term “asymmetric externalities.” Within this distributional asymmetry, we find that environmental survival pressure in rural Mongolia renders perceived environmental costs irrelevant to the migration decision: the marginal environmental cost of relocation is near zero, while benefits remain tangible and immediate. This survival-driven calculus differs categorically from the opportunity-driven migration observed in institutional contexts such as China. We also find that urban concentration generates national-level resilience, buffering development indicators against systemic shocks while localizing environmental and infrastructural burdens. These findings challenge prevention-focused urbanization policies, suggesting that under state capacity constraints, urban concentration functions as a de facto development strategy whose trade-offs require management rather than reversal.