This D3.js pie chart visualizes the top 10 countries by 2020 air pollution deaths, sourced from a GitHub-hosted CSV. The code uses the `d3.pie` layout and `d3.arc` generator to draw the chart's sectors, with colors assigned via `d3.scaleOrdinal`. A legend displays each country and its corresponding death count, formatted with `d3.format`. The chart is rendered as SVG, and the data is loaded asynchronously using the `d3.csv` method.