This bubble chart visualizes the environmental impact of urban parks by plotting park area on the x-axis, annual visitors on the y-axis, and tree density as bubble size, with color encoding city. Each circle represents a park from the loaded CSV data, and hovering reveals the park name and air quality index via a tooltip. Built with D3 v7, the visualization uses d3.scaleLinear for axes and bubble radius, d3.scaleOrdinal with d3.interpolateTurbo for city colors, and includes legends for tree density and city categories.