This example visualizes asthma prevalence across countries using an interactive Leaflet map, with data drawn from a static JSON table. The map displays colored country polygons based on prevalence values, and users can explore the geographic distribution of the data. The code integrates Leaflet for map rendering and tile layers, alongside D3.js for data manipulation, while loading GeoJSON country boundaries from an external script. A legend and info control provide context for interpreting the prevalence ranges shown on the map.