This choropleth map visualizes world population data from a CSV file, displaying countries in a sequential blue color scale based on their population size. It renders an SVG with D3 v6, using `d3.geoNaturalEarth1` and `d3.geoPath` to draw country boundaries from TopoJSON world-atlas data. Interactive tooltips appear on mousemove, showing country names and population values, while a gradient legend indicates the color scale up to 1.5 billion people.