This example displays a choropleth map of India, coloring each state with a categorical color scale. The map uses the Mercator projection to render geographic boundaries from a TopoJSON file. The visualization is built with React, D3 v5, and the `topojson` library, which parse the data and generate SVG paths. The `d3.geoPath` and `d3.geoMercator` functions handle projection and rendering, while a CSS hover effect highlights individual states in yellow.