This stacked bar chart shows pollution rating distributions across six Texas cities, with each bar segmented into five pH-level categories from below 5.0 to above 8.5. The visualization uses d3.stack() to compute the stacked series, d3.scaleOrdinal with a categorical color palette for the rating bands, and d3.scaleBand for the city axis. Hover interactions on individual rectangles trigger a custom tooltip displaying the exact percentage for that rating category, while the legend identifies each segment’s color. Data is loaded from a CSV file using d3.csv, and the chart is rendered as SVG with margins, axes, and labels configured through D3 selection methods.