Urban regions face environmental challenges due to elevated carbon dioxide (CO₂) concentrations from human activities such as waste incineration and traffic, which contribute to local temperature increases and place pressure on urban ecosystems. This study investigated the effect of tree-based carbon sequestration in reducing CO₂ concentrations within a residential complex divided into four sections (A, B, C and D), all exposed to multiple pollution sources. For each section, comprehensive field data were gathered, including direct CO₂ readings from several sites using portable devices and the physical attributes of the trees to estimate their sequestration capacity non-destructively, accounting for tree age and number. Section A (higher density of trees) demonstrated the highest sequestration rate of 2061.5 kg/year, with significantly reduced CO2 levels despite being close to heavy traffic. Conversely, section D (fewer trees spread across a broad area) showed higher CO₂ concentrations and a significantly lower sequestration at 678.3 kg/year. Additionally, the study found that CO2 concentrations near trees were consistently the lowest in all sections compared to the rest of the sites, with decreases ranging from 1.93% to 0.60%. This highlighted the localised impact of trees in reducing gas concentrations. Sections near waste incineration activities, particularly section C, exhibited a low sequestration capacity to mitigate the significant increases in CO₂ concentrations. Therefore, urban tree density should be enhanced, especially in high-emission areas, waste incineration plants should be relocated away from residential zones, and targeted pollution management measures should be implemented to improve urban environmental sustainability.