Walking from Manhattan to Harlem vividly showcases the stark contrasts and persistent inequalities faced by minority communities in New York City [ 1,2,3]. The journey reveals visible racial segregation, differing shop compositions, and higher prevalence of smoking and substance use in Harlem [ 4,5,6,7]. The disparities extend to street cleanliness, noise levels, police presence, unemployment rates, real estate values, and a palpable sense of insecurity. Historical contexts of segregation and economic disparities, discriminatory policies, and underinvestment have entrenched these inequities. Educational opportunities are starkly different, with Harlem schools often underfunded [ 8,9]. Targeted marketing by particular industries exacerbates health issues [ 10,11,12,13,14,15,16,17]. The journey underscores the concept of Minorities' Diminished Returns (MDRs) [ 18,19,20,21], where social context diminishes the benefits of personal assets for minority individuals. Addressing these issues requires comprehensive, sustained interventions to promote racial equity.

As we walked from Manhattan to Harlem, the transition from a predominantly White to a predominantly Black and Hispanic neighborhood was unmistakable. The visible racial segregation between these areas is a manifestation of historical and systemic inequalities that continue to shape the city's demographic landscape [ 22]. This segregation has deep roots in discriminatory housing policies, economic disparities, and social exclusion, leading to concentrated areas of poverty and limited opportunities for minority populations [ 23]. Addressing these structural issues is crucial for promoting racial equity and improving the health and well-being of all residents.

In Harlem, the composition of shops differs markedly from that in Manhattan. While Manhattan boasts a variety of stores, including high-end retailers and diverse eateries, Harlem's commercial landscape is dominated by fast-food outlets, churches, hair salons, and small delis or grocery stores with limited selections [ 24,25]. Fresh vegetables and other healthy food options are notably scarce [ 26]. This disparity in food availability, often referred to as a "food desert," contributes to poor dietary habits and higher rates of obesity and related chronic diseases among Harlem residents. Policies aimed at increasing access to affordable, nutritious food are essential to combat these health disparities [ 27].

The prevalence of smoking, particularly tobacco, is notably higher in Harlem compared to Manhattan, where it is almost absent [ 28]. Additionally, the pervasive smell of marijuana in the air highlights a significant difference in substance use patterns between the two areas [ 29,30]. Higher rates of smoking and substance use in Harlem are indicative of broader social and economic stressors that disproportionately affect minority communities [ 31,32]. These behaviors are linked to a range of health issues, including respiratory diseases, cardiovascular problems, and mental health disorders [ 33]. Public health interventions targeting smoking cessation and substance use prevention must be tailored to address the unique challenges faced by these communities.

The streets of Harlem appeared dirtier and noisier compared to those in Manhattan. The presence of litter, combined with loud noises from traffic and street activities, creates a stressful and unhealthy living environment [ 34]. Poor street cleanliness can attract pests and contribute to the spread of infectious diseases, while excessive noise has been linked to adverse health outcomes such as hypertension, sleep disturbances, and mental health issues [ 35]. Enhancing sanitation services and implementing noise reduction strategies are critical steps toward creating a healthier urban environment for Harlem residents.

A notable difference in the level of police presence was observed between Manhattan and Harlem. In Harlem, there seemed to be a higher concentration of police officers, which could be interpreted as both a response to and a cause of community dynamics [ 36]. While increased policing is often intended to enhance public safety, it can also contribute to a sense of mistrust and tension between law enforcement and community members, particularly in minority neighborhoods [ 37]. Efforts to build positive relationships between police and residents, alongside community-based safety initiatives, are vital for fostering a sense of security and cooperation.

Groups of unemployed men were a common sight in Harlem, reflecting the area's high unemployment rates [ 2]. Economic disparities, including limited access to job opportunities and educational resources, exacerbate unemployment issues in minority communities [ 37]. High unemployment not only affects economic stability but also has significant health implications, contributing to mental health problems, increased substance use, and overall lower quality of life [ 38]. Policies focused on job creation, vocational training, and educational support are necessary to address these economic inequities and improve community health outcomes [ 39].

The disparity in home values and real estate prices between Harlem and Manhattan starkly illustrates the wealth gap between Black and White populations [ 40]. In Manhattan, real estate prices are among the highest in the country, with luxury apartments and high-end commercial properties reflecting the significant wealth concentrated in the area [ 23]. Conversely, Harlem, despite its proximity to Manhattan, has historically lower property values, a consequence of decades of redlining, discriminatory lending practices, and economic disinvestment [ 23,41]. This difference in home values not only highlights the immediate economic disparity but also underscores the broader, systemic inequities that have prevented Black families from accumulating wealth through property ownership at the same rate as White families [ 42,43]. The wealth gap is thus perpetuated across generations, as lower home values in predominantly Black neighborhoods limit opportunities for wealth accumulation, reinforcing cycles of poverty and economic disadvantage.

The sense of insecurity in Harlem, particularly after dark, was palpable [ 44,45]. This perception of danger limits people's movements and can deter engagement in outdoor activities, contributing to social isolation and reduced physical activity [ 46]. Fear of crime is a significant barrier to community cohesion and well-being [ 47,48]. Comprehensive approaches to improving neighborhood safety, including environmental design, community policing, and social programs, are essential to alleviate these fears and promote a safer, more active community.

The emergence of segregation in Harlem and other minority neighborhoods can be traced back to a series of discriminatory policies and practices, including redlining, restrictive covenants, and urban renewal projects that displaced minority communities. These policies systematically excluded Black and Hispanic families from economic opportunities and homeownership, leading to concentrated poverty and limited social mobility. Additionally, underinvestment in these communities has perpetuated cycles of disadvantage, with inadequate infrastructure, poor housing conditions, and limited access to quality education and healthcare services [ 7,49,50,51,52,53].

The experience of police practices, particularly the controversial stop-and-frisk policy, has disproportionately targeted Black men in Harlem. This practice not only fosters a sense of mistrust and fear among community members but also contributes to the criminalization of minor infractions [ 54,55,56,57,58]. The frequent police stop create an environment of surveillance and control, further marginalizing residents and exacerbating social inequalities. Reforming police practices to prioritize community engagement and de-escalation strategies is essential for rebuilding trust and ensuring justice.

In Harlem, the prominence of churches and beauty establishments like hair salons reflects the community's adaptive strategies to economic and social marginalization. Religion [ 59,60,61,62,63,64] and beauty [ 65,66,67] have become significant sources of cultural identity, social support, and economic activity. These institutions play a crucial role in fostering community cohesion and resilience but also highlight the limited economic diversification and investment in broader job opportunities and industries. Enhancing economic development initiatives to support a wider range of businesses and services can help diversify the local economy and provide more employment opportunities.

Educational opportunities in Harlem are starkly different from those in more affluent areas like Manhattan. Schools in Harlem often suffer from underfunding, inadequate facilities, and lower academic performance, limiting students' prospects for higher education and economic advancement [ 68,69,70]. The cycle of educational disadvantage is perpetuated by systemic inequities, including biased funding formulas, lack of access to advanced coursework, and insufficient support for teachers and students. Addressing these disparities requires comprehensive education reform, equitable funding, and targeted support programs to ensure all students have access to high-quality education.

The targeting of minority communities by the tobacco and marijuana industries is a predatory practice that exploits social and economic vulnerabilities. In Harlem, aggressive marketing campaigns for tobacco products and the proliferation of marijuana dispensaries contribute to higher rates of substance use and related health issues [ 71,72]. These industries often use deceptive advertising and promotion strategies to normalize substance use and undermine public health efforts [ 72]. Implementing stricter regulations on marketing practices and increasing public health education and prevention programs are critical to reducing the impact of these harmful industries.

The observed disparities between Manhattan and Harlem are not recent developments but are deeply entrenched in a historical context of systemic discrimination and socio-economic neglect. Over time, discriminatory policies such as redlining, underinvestment in education, targeted marketing by harmful industries, and aggressive policing have coalesced to form a complex web of causation that shapes the current realities of these neighborhoods. This historical context has given rise to a unique culture of adaptation and resilience in Harlem, characterized by reliance on community institutions like churches and beauty establishments [ 73]. However, this deeply rooted context means that while policy recommendations are essential, their immediate effects may be limited. Meaningful change requires sustained, long-term interventions that address the underlying structural issues and gradually work to dismantle the systemic inequalities that have persisted for generations. Only through comprehensive, persistent efforts can we hope to significantly reduce these disparities and foster a more equitable society.

The observed disparities between Manhattan and Harlem are not recent developments but are deeply entrenched in a historical context of systemic discrimination and socio-economic neglect. Over time, discriminatory policies such as redlining, underinvestment in education, targeted marketing by harmful industries, and aggressive policing have coalesced to form a complex web of causation that shapes the current realities of these neighborhoods. This historical context has given rise to a unique culture of adaptation and resilience in Harlem, characterized by reliance on community institutions like churches and beauty establishments. However, this deeply rooted context means that while policy recommendations are essential, their immediate effects may be limited. Meaningful change requires sustained, long-term interventions that address the underlying structural issues and gradually work to dismantle the systemic inequalities that have persisted for generations [ 74,75,76]. Only through comprehensive, persistent efforts can we hope to significantly reduce these disparities and foster a more equitable society.

The impact of social context and structure often outweighs personal assets, making it possible for even highly educated individuals to be trapped in the systemic inequities of neighborhoods like Harlem. Consider a highly educated Black professional residing in Harlem or a child from a high-SES Black family who spends time in such an environment. Despite their education and income, the social milieu exerts a powerful influence. In Harlem, where friends might smoke and vape, the child is exposed to higher rates of substance use and other risk behaviors, which can undermine their health and future opportunities. The family's wealth, though significant, is still constrained by the lower property values and economic conditions of their neighborhood, limiting their ability to leverage their assets in the same way a similarly educated and affluent White family might in Manhattan. This disparity illustrates the concept of Minorities' Diminished Returns (MDRs) [ 77,78,79,80], where the benefits of education and income are less pronounced for minority individuals compared to their White counterparts. Even with similar levels of education, the quality of life and opportunities available to Black families in Harlem are substantially different from those available to White families in Manhattan [ 81,82]. This is due to the entrenched structural inequities that shape daily life, including access to quality education, safe environments, and healthy social networks. Thus, MDRs [ 21,83] are starkly evident when comparing the lives of Black and White individuals with similar educational attainments across these two neighborhoods, highlighting the profound impact of social context and structural barriers on perpetuating racial disparities. Extensive body of research supports diminished returns of education, employment and income for Black populations [ 81,84,85,86,87,88,89,90,91,92,93,94,95,96].

The walk from Manhattan to Harlem is an injustice and inequality tour [ 97,98]. It vividly highlights the persistent inequalities and challenges faced by minority communities in New York City. Addressing these issues requires a multifaceted approach, integrating policies that promote racial equity, improve access to healthy food, reduce substance use, enhance urban cleanliness and safety, and support economic opportunities. By acknowledging and addressing these disparities, we can work towards a more equitable and healthy city for all its residents.

Funding: Hossein Zare received funding from the National Institute of Health (NIMHD) grant U54MD000214.