A scatter plot displays the relationship between PM10 and NO2 air pollution levels, with each point shaped according to the country name using D3’s `scaleOrdinal` and `symbolsFill` generators. The visualization renders in an SVG via `d3.scaleLinear` for axes, with a custom legend built from `symbol` shapes. Data is fetched from a GitHub-hosted CSV and parsed with `d3.csvParse`. The code relies on reusable modules for axes and legend rendering, demonstrating modular D3 v7 chart composition.