A D3.js scatter plot visualizes the relationship between mileage and selling price for used cars, with each circle representing a vehicle and its color indicating the number of previous owners. The plot maps kilometers driven on the x-axis and selling price in millions of Indian Rupees on the y-axis. The code uses d3.csv to load car details, d3.scaleLinear for both axes, and d3.axisLeft and d3.axisBottom to render tick marks. Circles are appended as SVG elements with fill-opacity to show overlapping points, and the chart fills the browser window.