Abstract: The present study deals with the ambient air quality monitoring with respect to heavy metals (Pb, Ni and As) concentrations in PM₁₀ at seven locations of NCR region, a National Capital Region of India. The 24 hr mean concentrations of PM₁₀ ranged between 126 to 237.67 μg m-3, which is beyond the permissible limit(100 μg m-3) of national ambient air quality standards (NAAQS) also found higher than the prescribed annual daily limit of US EPA (50 μg m-3). The ambient air was mostly dominated by the Ni and least by the As among the metal analysed. Ghazipur, a dumping site and also influenced by heavy vehicular transportation due to near highway, is found to be the most polluted area of NCR region and Mayur vihar phase-I, Delhi the least. The ambient air of Ghazipur is rich in Ni, indicating contribution of dumping and also mobile sources. The Indrapuram, Ghaziabad a residential place near the industry, is rich in Pb but within the permissible limit, suggesting contribution of point sources. The Ni concentration is found to be alarmingly high in the air at three locations i.e. Ghazipur, Vasundhra (Ghaziabad) and Noida Sec-26, when compared with the WHO limits (10 ng m-3). The As concentration is found to be below the detection limit at all locations. The present study has focused on to understand the concentrations of heavy metals in ambient air and also to analyse the quality of air in NCR region due to presence of huge vehicular transportation and industralisation, which is extremely harmful due to their toxic and carcinogenic nature.