A horizontal bar chart displays the top 10 most populous countries from a CSV file using D3 v5. The chart uses `d3.scaleBand` for y-axis categories and `d3.scaleLinear` for population values, with formatted tick labels converting values to billions. Bars are rendered as SVG rectangles in steel blue, with axis labels and a title included. The code loads data via `d3.csv` and applies a custom tick format to abbreviate large numbers.