This bar chart displays the top 10 most populous countries in 2020 using D3 scales and React components. The code loads United Nations population data via `d3.csv`, slices the dataset, and renders SVG rectangles with `scaleBand` for the y-axis and `scaleLinear` for the x-axis. Axes are manually drawn by mapping tick values from `xScale.ticks()` and `yScale.domain()`, with React handling state through `useState` and `useEffect`. The visualization demonstrates combining D3’s data-driven utilities with React’s declarative rendering for interactive web graphics.