This study investigates the impact of vehicular-released heavy metals (Zn, Fe, Pb, Cd, and Ni) on foliar physiological and biochemical parameters of Conocarpus erectus and its relationship with the Air Pollution Tolerance Index (APTI). Leaf samples were collected from six sites along a busy road (Bahawalpur to Rahim Yar Khan, KLP Road) in Punjab, Pakistan, during the spring season, with control samples taken 50 m away from the roadside. Heavy metal concentrations were analyzed using an Atomic Absorption Spectrophotometer (AAS), revealing significantly higher levels of Pb, Cd, Ni, and Cu in leaf dust at polluted sites, particularly in Ahmadpur. Exposure to heavy metal pollution led to notable reductions in shoot length, leaf area, and biomass, with Khanbella exhibiting the most severe declines. Gas exchange parameters were altered, with increased CO