Medicinal Plants as Bio-Indicators of Urban–Industrial Air Pollution: Morphological, Anatomical, and Phytochemical Perspectives from Indian Industrial Regions

Abstract

Industrialization, urbanization, and vehicular emissions have depleted the environment in the case of air quality, markedly in major industrial zones in India. Conventional monitoring systems are rather precise but usually fail to take into account the cumulative biological effect of pollutants. Due to their sensitive physiology, metabolic diversity, and continuous exposure to atmospheric conditions, medicinal plants are considered reliable bio-indicators of air pollution. The consideration brought forth in this part is to make known the multi-faceted effect of urban–industrial air pollutants, especially the fine particulate matter (PM2..5), sulfur dioxide (SO2), and nitrogen oxides (NOx), on the selected Indian medicinal plants from field conditions such as Azadirachta indica, Ocimum sanctum, and Ficus religiosa. In passing, the study analyzes morphological symptoms, physiological disruptions through stomatal occlusion, and the decreases in phytochemical constitution, with special note to the antioxidant inductions. The paper summarizes with the Air Pollution Tolerance Index (APTI) tolerant and sensitive species to be cultivated for conservation in a green belt and early warning systems. The proposed study is focused on the thresholding by these medicinal plants that are bestowed with pollution-ending protection potentials, whereas phytochemical pollution poses a challenge for the continuation of therapeutic and clinical science-based evidence on field trials and suggests an urgent call for regulatory and ecological interventions.