From Sprawl to Sustainable Urbanization in the Global South: Migration, Urban Growth, and Environmental Governance in Pakistan

Rapid migration-driven urbanization in developing nations poses significant challenges to environmental sustainability and policy effectiveness. This study investigates the interplay between migration, urban growth, and environmental policy in Karachi and Quetta, Pakistan—two cities with distinct urbanization trajectories. Integrating an adapted Pressure-State-Response (PSR) framework with a mixed-methods approach, the research combines survey data from 400 residents, geospatial analysis of land-use change (1992–2022), and secondary data, analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM). The findings reveal that urban growth (State) significantly mediates the relationship between migration (Pressure) and perceived environmental policy effectiveness (Response). Crucially, the City Type (Karachi vs. Quetta) significantly moderates the strength of the Pressure→ State→ Response pathway, revealing that the fragmentation of governance in Karachi and the resource scarcity in Quetta lead to distinct outcomes. The analysis also reveals that fragmented governance impedes effective policy responses, challenging the applicability of universal models like the Environmental Kuznets Curve (EKC) in such contexts. These findings underscore the necessity for context-specific, integrated urban planning that actively incorporates migration dynamics, strengthens governance, and promotes social equity to achieve sustainable development.