In a groundbreaking study poised to reshape our understanding of urban environmental dynamics, researchers Li, Wei, Chen, and colleagues have unveiled striking disparities that persist between urban centers in the Global South and Global North. Their comprehensive analysis spanning over 10,000 cities worldwide reveals multiple layers of environmental inequality that demand urgent scientific and policy attention. Published in the prestigious npj Urban Sustainability in 2025, this work deploys unprecedented data integration and sophisticated analytical frameworks to expose stark ecological divides previously masked by aggregate global statistics.
The methodological rigor of this study is particularly notable. The team amalgamated extensive environmental datasets including air quality indices, green space distribution, water accessibility, and waste management efficacy. Employing machine learning algorithms alongside geospatial analytics allowed them to uncover nuanced patterns of environmental hazards and resource disparities across urban landscapes, which often align unequally along geopolitical and economic fault lines. These approaches enabled a granular comparison not only across continents but within diverse urban typologies ranging from megacities to mid-sized urban clusters.
Central to the findings is the persistent inequality in air pollution exposure. Cities situated in the Global South, often characterized by rapid urbanization combined with weak regulatory frameworks, suffer from significantly higher concentrations of particulate matter (PM2.5), nitrogen oxides, and sulfur dioxide emissions. In contrast, major urban centers in the Global North display relatively lower pollutant levels, attributable to stricter environmental policies and advanced technological mitigation practices. This dichotomy underscores the double burden borne by Global South populations who face disproportionate health risks including respiratory diseases and cardiovascular conditions linked to poor air quality.
Beyond air pollution, the study reveals glaring disparities in urban green space availability. Public parks and natural vegetative areas, essential for urban heat mitigation and mental well-being, are markedly scarce in many Global South cities. The data highlight that residents in these areas endure elevated urban heat island effects, exacerbating thermal stress during global warming-induced heatwaves. Conversely, cities in the Global North benefit from well-preserved and managed green infrastructure that buffers climatic extremes and enhances biodiversity, spotlighting a critical environmental inequality dimension with profound social repercussions.
Water resource accessibility presents another axis of environmental disparity documented by Li et al. In over half of the surveyed cities within the Global South, reliable access to clean potable water remains sporadic or limited. Aging infrastructure, insufficient sanitation, and contamination risks combine to degrade water quality and availability, deepening public health vulnerabilities. On the other hand, most Global North urban centers report robust water management systems backed by strong governance, advanced purification technologies, and systematic infrastructure maintenance, reflecting an entrenched infrastructural divide that fuels social inequities.
The investigation also dissected waste management patterns, revealing the contrasts in recycling rates, waste treatment, and landfill practices. Cities in the Global North achieve higher efficiencies in material recovery and sustainable waste processing, paralleling investments in circular economy initiatives. In stark contrast, burgeoning urban centers of the Global South often grapple with inadequate waste collection services and environmentally hazardous disposal methods, including open dumping and burning, which exacerbate air and soil pollution and threaten ecological health. The findings suggest urgent need for technology transfer and capacity building to bridge this divide.
An especially compelling aspect of the research is the integration of socio-economic variables with environmental indicators, shedding light on the intersectionality of urban inequality. Poverty, informal settlements, and limited institutional capacity intensify the environmental burdens shouldered by marginalized populations in the Global South. These social determinants entrench vulnerability to environmental hazards and undermine resilience to climate change impacts, revealing a complex mosaic where urban sustainability cannot be decoupled from social justice imperatives.
The authors caution against oversimplified narratives that paint urban growth in the Global South solely as a challenge; rather, they champion a vision of sustainable urbanization grounded in equity, innovation, and local empowerment. By leveraging community knowledge, decentralized governance, and context-sensitive environmental technologies, cities in the Global South may turn these environmental inequalities into opportunities for green transformation. This requires sustained investment, inclusive policy frameworks, and international cooperation to support adaptive infrastructure and social welfare enhancements.
Critically, the study advocates for the development of globally standardized environmental metrics that capture both exposure and vulnerability dimensions with spatial resolution adequate for policymaking. The current patchwork of measurement standards impedes cross-regional comparisons and undermines coordinated global responses. The authors propose an integrated urban sustainability index framework equipped to guide resource allocation and monitor progress toward equitable environmental health outcomes across diverse urban contexts.
This research also touches on the role of urban planning paradigms in perpetuating or alleviating disparities. It reveals that urban centers in the Global North often benefit from long-standing planning traditions emphasizing environmental protection, green corridors, and transportation networks optimized for emission reduction. In contrast, rapid and often unregulated urban expansion in many Global South cities undermines ecological integrity and fails to incorporate green infrastructure adequately, highlighting critical governance and capacity gaps that shape environmental inequalities.
Furthermore, the authors highlight the intersection of climate change with existing urban environmental inequalities. Many cities in the Global South already experiencing adverse environmental conditions face amplified climate risks such as intensified flooding, droughts, and heatwaves. The inadequate adaptive capacity evident in infrastructural and social systems strengthens the urgency for integrated climate resilience strategies designed with environmental justice at their core.
The implications of this study extend into public health domains, underscoring urgent needs for cross-sectoral collaboration between urban planners, public health officials, and environmental scientists. The disproportionate disease burdens linked to environmental degradation in the Global South urban populations call for targeted interventions that integrate pollution control, poverty alleviation, and access to essential services within urban development agendas.
Li and colleagues’ work also prompts reconsideration of funding paradigms and international development aid focusing on urban sustainability. Their findings highlight the necessity for tailored support mechanisms that reflect the unique environmental challenges faced by Global South cities, moving beyond generic “one-size-fits-all” approaches toward differentiated strategies that prioritize equity and local context.
Education and community engagement emerge as pivotal themes for effective environmental governance in urban centers globally. The study suggests that participatory approaches empower disadvantaged communities, fostering stewardship and facilitating adoption of sustainable practices. Elevating local voices ensures that urban sustainability policies resonate with lived realities and promote inclusiveness.
In conclusion, this landmark study by Li, Wei, Chen, and their research team offers a powerful evidentiary foundation exposing entrenched environmental inequalities between Global South and Global North urban centers. With implications cutting across environmental science, public health, urban planning, and global development, it calls for holistic and justice-centered strategies to achieve urban sustainability in the century ahead. Their insights chart a roadmap to a truly inclusive urban future where equitable environmental quality forms the cornerstone of human wellbeing around the world.
Subject of Research: Environmental inequalities in urban centers between the Global South and Global North
Article Title: Multiple environmental inequalities between Global South and Global North in over 10,000 urban centers
Article References:
Li, W., Wei, Y., Chen, L. et al. Multiple environmental inequalities between Global South and Global North in over 10,000 urban centers. npj Urban Sustain (2025). https://doi.org/10.1038/s42949-025-00302-z
Image Credits: AI Generated
