This bar chart displays the top 10 most populous countries in 2020, using horizontal bars scaled by population. The visualization ranks countries from largest to smallest, with a formatted x-axis labeling population values in billions. Built with React and D3 v5, the code uses `scaleBand`, `scaleLinear`, and `csv` to load and map data from the UN World Population Prospects 2019 dataset. SVG rendering handles the axes and rectangular marks, while CSS styling applies a teal fill and Poppins font throughout the chart.