This interactive chart displays the top 5 most populous countries based on 2019 data, using horizontal bars to compare population sizes. The visualization loads data from a CSV file via `d3.csv`, then renders an SVG bar chart with React. It employs `d3.scaleBand` for the categorical country axis and `d3.scaleLinear` for the population values, with gridlines and tick labels generated from the scales. The chart updates reactively as data loads, showing a loading state before the bars appear.