The book describes effects of air pollutants on some plants studied at four residential and seven commercial locations. The effect of four air pollutants namely SPM, RSPM, SOx and NOx were ascertained on Azadirachta indica, Cassia fistula, Ficus religiosa, Delonix regia and Polyalthia longifolia plants growing on road sides at 11 selected locations with a control (non-polluted) site. Variation in concentrations of these pollutants in relation to years, seasons and locations is explained with appropriate statistical treatment. Effect of air pollutants on plants have been given in terms of changes in leaf characters of different plant species as compared to reference site. The publication contains computation of Air Pollution Tolerance Index and its use in identification of relative tolerance of plant species. Best Subsets Linear Regression technique was used to identify the major pollutants influencing various leaf characters in different species and develop a model to predict the effect of air pollutants on plants. In the light of findings appropriate mitigation measures have been suggested.