Twenty years of urban noise and soundscape mapping research in developing countries: methods, trends, and research gaps

This study systematically reviews 257 peer-reviewed articles indexed in the Scopus database and published between 2005 and 2025 to characterise research trends, methodological paradigms, geographic distribution, and indicator usage in urban noise and soundscape mapping. The temporal analysis shows that the topic first emerges in 2005 with pioneering studies from Nigeria and Brazil, followed by a pronounced rise in publication activity after 2016, driven primarily by developments in China, India, Brazil, and several Southeast Asian countries. Methodologically, the field has shifted from diagnostic measurements toward integrated systems incorporating in - situ monitoring, GIS, simulation tools, and, more recently, machine-learning methods. Experiential and soundscape-based studies remain limited but are gradually expanding, whereas policy-oriented and health-integrated assessments are still rare. Overall, the review identifies four persistent challenges: geographic and thematic imbalance, limited integration of perceptual and socio-spatial dimensions, weak policy translation, and a notable absence of health and wellbeing focused, human-centered mapping. Addressing these gaps is essential for producing robust, comparable, and policy-relevant acoustic evidence capable of informing urban planning and environmental-health strategies across the Global South.