This visualization shows the ten most common categories of unhealthy Air Quality Index (AQI) days for PM2.5 pollution in Texas, presented as a pie chart with a legend listing each category and its corresponding day count. The data is loaded from a CSV file and sorted in descending order before rendering. Using D3 v5, the code employs `pie`, `arc`, and `scaleOrdinal` with `schemeCategory10` to generate the chart and legend. The visualization is built with React, rendered as SVG, and includes interactive mouseover logging to the console.