Provides a comprehensive framework for Air Quality Index (AQI) analysis from air pollutant concentration data using Central Pollution Control Board (CPCB) criteria. Calculates pollutant-specific AQI sub-indices and derives the overall AQI and its category, identifies the primary pollutant, and summarises, ranks, and visualizes results across monitoring locations. Methodology follows Central Pollution Control Board (2014,"National Air Quality Index") < https://app.cpcbccr.com/ccr_docs/FINAL-REPORT_AQI_.pdf>.