This D3.js pie chart visualizes the top 10 countries by air pollution deaths in 2020, with each slice labeled with the death count in thousands. The chart uses `d3.pie`, `d3.arc`, and `d3.scaleOrdinal` to generate the arcs, segment paths, and categorical colors. A custom legend, built with SVG rectangles and text elements, lists each country alongside its corresponding value, while the data is fetched from a CSV URL using `d3.csv`.