Housing constitutes the foundational material condition of urban life in India, determining not only shelter quality and tenure security but also access to employment, education, healthcare, and social networks that collectively define the social mobility pathways available to the 500 million Indians who now live in urban areas. India's rapid urbanisation — with the urban population projected to reach 600 million by 2031 — has outpaced formal housing production dramatically, generating one of the world's largest informal settlement populations. An estimated 65 million Indians live in slums and unauthorised colonies, according to the 2011 Census, a figure widely considered an undercount given the exclusion of non-notified informal settlements from official enumeration. This study presents a comparative cross-city analysis of housing inequality indicators, informal settlement prevalence, and social mobility outcomes across forty Indian cities and twenty cities from comparable emerging economies, drawing on National Family Health Survey, Census of India, and National Sample Survey data supplemented by World Bank and UN-Habitat global urban datasets covering the period 2015-2023. Multi-level regression models examined the associations between housing cost burden (rent-to-income ratio), informal settlement share, and measures of intergenerational educational mobility, occupational attainment gaps between housing tenure groups, and subjective wellbeing outcomes. Results demonstrate that Indian cities with rent-to-income ratios above 0.40 show significantly lower intergenerational educational mobility, and that informal settlement share is the strongest single predictor of educational attainment gap between housing tenure groups.