A horizontal bar chart shows the top 21 countries by CO2 emissions in 2018, using data from UCSUSA. Each bar’s length encodes emissions in gigatons, with countries ranked from China (10.06 Gt) down to Kazakhstan. The visualization uses D3 v6’s `scaleBand` for the y-axis, `scaleLinear` and `max` for the x-axis, and `axisBottom` with a custom tick formatter. Cities are rendered as SVG rectangles, with axis labels and a title added via appended text elements. The CSV data is loaded using `csv`.