The visualization displays hourly air quality measurements from a Seoul monitoring station as a horizontal chart, with each line representing a pollutant such as SO2, NO2, or PM2.5 across time. Users can zoom into specific date ranges using a dual-handle time slider that filters the displayed data. The rendered SVG chart uses D3.js v7’s `d3.drag` for interactive range selection, `d3.group` to organize data by pollutant and date, and a custom `multitext` function for labeling. The underlying data comes from a CSV file containing pollutant concentrations and timestamps.