This visualization overlays a semi-transparent bar chart and a line graph to show changes in a percentage metric across overlapping time periods, with each bar labeled and tooltips revealing start and end dates. The React app loads JSON data containing survey periods (e.g., NFHS3, NFHS5) and uses d3.scaleTime, d3.scaleLinear, and d3.line to draw SVG elements. Animated hover interactions are handled via React’s onMouseOver and onMouseOut, while d3’s selection API manages the tooltip’s opacity transitions.