Air pollution is a significant matter of concern in today's world. The current study objective is to determine the air pollution tolerance index (APTI) of Kolkata from five roadside medicinal plants, namely, Heliotropium indicum, Tridax procumbens, Cleome rutidosperma, Commelina benghalensis, and Euphorbia hirta. APTI was determined by fresh leaves extracts using four important plants physiological parameters such as relative water content, ascorbic acid (AA) content, total chlorophyll (Chl) content, and pH of leaf extracts. Three sites or areas were selected for the study in Kolkata. It includes a control area (Jadavpur), a moderately polluted area (Salt Lake, Sec V), and highly polluted area (Dunlop Bridge) based on the West Bengal State Pollution Control Board databases and previous study reports. For estimating Chl and AA content spectrophotometer and titration method were used, respectively. A higher APTI value was found in plants located at the control area and moderately polluted area. However, the lower amount of APTI value was found in plants located in the polluted area. The study concludes that air pollution has a severe impact on plant and human health. The plant species with high APTI value can be planted around industrial complexes, roadsides, and urbanized sites to monitor air pollution in greener and cost-effective way.