Forest and urban vegetations play a vital role in regulating the carbon cycle as a source or sink of carbon dioxide (CO2), primarily through processes like photosynthesis and respiration. This ecosystem service can be enhanced by planting more trees as a part of the afforestation program or ecorestoration. The underlying soil compartment of the vegetation also serves as a unique sink of carbon. We present in this chapter the stored carbon in the above-ground biomass (AGB) of Acacia auriculiformis sampled from ten different locations in the maritime state of West Bengal, India, during 2024. The CO2 level of the near-surface atmosphere was also measured simultaneously to evaluate the ambient air quality in terms of CO2 level. We observe significant positive correlations between stored carbon and the soil organic carbon (SOC), indicating an appreciable contribution of the trees’ carbon to the underlying soil compartment through litters and detritus. The significant negative relationship between the stored carbon of A. auriculiformis and the near-surface atmospheric CO2 confirms the species’ potential as a unique sink of carbon. We infer that the stored carbon in the species is drawn from the CO2 reservoir of the ambient atmosphere, due to which the negative correlation has been generated as the output. We suggest mass plantation of the species as a cost-effective nature-based solution (NbS) to modulate the atmospheric CO2 level at the local scale.