This bar chart displays population estimates for ten countries, with each bar colored steel blue by default. Hovering a bar highlights it in red with a blue outline and displays a text label showing the country’s population in billions, using the `format` function from d3. The chart uses `d3.scaleBand` for the x-axis, `d3.scaleLinear` for the y-axis, and `d3.axisLeft` and `d3.axisBottom` for ticks, with a custom Indian digit-grouping function in `format-india.js`.