Urban air pollutants like particulate matter, sulphur dioxide, nitrogen oxides, ozone etc. can harm the plants but severely effects the human health. It can absorb through stomata and affects adversely its biochemical constituents and physiological process. The variation in biochemical parameters in the leaves can be used as indicators of air pollution for early diagnosis of stress or as a marker for physiological damage prior to the onset of visible injury symptoms. Tree species resistivity and susceptibility level to air pollution within avenues of Bangalore has been evaluated on the basis of Air Pollution Tolerance Index (APTI) value. Four parameters namely Leaf extract pH, Total Chlorophyll Content (TCh), Relative Water Content (RWC) of Leaf and Ascorbic Acid content were determined and APTI was computed. The tree species with higher APTI values like Samanea saman, Bougainvillea glabra, Tabubea argentia, Peltophorum pterocarpum, Bauhinia acuminata and Polyalthia longifolia were tolerant to air pollutants and can be used as effective indicators and pollution scavengers. The tree species having higher APTI value can be given priority for plantation program in newly urbanized areas and avenues of Bengaluru; effect of air pollution on stress and make the environment clean for healthy life.