This example shows an interactive horizon chart for air pollution data, letting users compare pollutant levels across six types (SO2, NO2, O3, CO, PM10, and PM2.5) for selected years. The visualization uses D3.js (v7) with an SVG rendering approach, displaying time-series data from a GitHub-hosted CSV dataset. It employs d3.rollup to aggregate measurements and d3.scaleTime for the x-axis, while a dropdown menu switches between annual datasets. The chart updates dynamically by redrawing the SVG elements when the user changes the year selection.