This animated horizon chart visualizes air pollutant concentrations (SO₂, NO₂, O₃, CO, PM10) over time, with each band color-coded by pollutant and overlaid to show temporal trends. Users toggle pollutants via switches and select time bands from dropdown menus. The chart is built with D3 v7, using SVG paths, interactive checkboxes, and a fixed tooltip to display values. The update mechanism triggers loaders and redraws the horizon bands dynamically, with pollutants rendered individually and stacked for comparison.