This visualization displays London’s monthly average PM2.5 particulate levels from 2010 through 2018 as multiple colored lines, one per year, overlaid on a shared time axis. It uses d3.csv for data loading, d3.nest and d3.line for grouping and path generation, d3.scaleTime, d3.scaleLinear for axes, and d3.scaleOrdinal for year-based color encoding. The view includes a dropdown menu, a color legend, and SVG rendering. Data derives from the Kings College London Air Quality Dataset via the London Datastore.