Air pollution has emerged as one of the most important aspects of environmental research, as the progress of human civilisation has significantly deteriorated the quality of air. Plants have a significant role in maintaining and monitoring ecological balance by actively participating in the cycling of gases such as oxygen and carbon dioxide and nutrients. Besides, they also provide a large leaf base for assimilation and deposition of airborne pollutants to reduce their concentration in the atmosphere. Plants, on the other hand, do not react to all types of pollutants. Hence, different plant species have different levels of potential to remediate a specific pollutant in the atmosphere. There are a variety of parameters on the basis of which plant species are selected for plantation. Before choosing any plant species for a plantation, each of these parameters should be thoroughly examined. Plants having greater air pollution tolerance index (APTI) values are more tolerant and act as a sink, whereas plants with lower APTI values are less tolerant and can be used to determine the air quality. With the help of the APTI method decisions regarding plant species, selection can be made while developing Green Belts around polluted or urban areas.