One of the major problems faced by the world today is air pollution. Plants play a vital role in monitoring the air pollution. Plants are the ones, which have the ability to reduce the effect of air pollution. As they involve in this process, they are highly injured. The level of injury in plants is been studied through Air pollution tolerance index (APTI). APTI value can be calculated using four bio-chemical parameter namely, ascorbic acid content, total chlorophyll content, pH and relative water content. The study was carried out in two different locations of south Chennai in five different plants such as Ixora coccinea (santan), Hibiscus rosa sinensius (shoe flower), Murraya koenigii (curry leaves), Plectranthus amboinicus (Indian borage), Bougainvillea glabra (Paperflower). The plants taken inside the college campus were considered as plants in Stella Maris College campus and plants along the road side platform were taken as highly polluted areas in Chennai. The results were compared for both the locations, in which there was decrease in all the parameters in the highly polluted areas in Chennai which was highly polluted compared to plants in Stella Maris College campus
