This bar chart displays the 2020 population of 30 countries, sourced from a CSV file fetched via `d3.csv`. The visualization uses D3 scales (`scaleBand`, `scaleLinear`) and custom React components (`AxisBottom`, `AxisLeft`, `Marks`) to render the SVG. Horizontal bars are drawn as `<rect>` elements, with tooltip text showing formatted values using D3’s `format` function. The chart includes styled gridlines, axis labels, and a "POPULATION-2020" title, all rendered through React’s declarative component structure.