The present study evaluates the ambient particulate matter (PM2.5) and associated elemental concentrations during the festival of Diwali (firecrackers bursting amid religious celebrations) during October–November in India. PM2.5 on Diwali day was 182 μg/m3, which is three times more than National Ambient Air Quality Standard (NAAQS) set by the government of India with metals contributing 22.7% to the PM2.5 load on 24 October 2022. Barium, potassium, strontium, aluminum and magnesium are major elements found in PM2.5. Multiple correlation and enrichment factor also gave similar results. Arsenic concentration exceeds the NAAQS along with cadmium (European Commission) and lead (USEPA) exceeds permissible standards during Diwali days. It is concluded that the bursting of fireworks during the Diwali celebration is a significant contributor to gaseous, and metal pollution, which includes hazardous elements like arsenic, cadmium, and lead. Although the population exposed to the pollution was at risk for a few days, significant health impacts can result from unfavourable weather conditions, as is typically seen in north India during the months of October through November. In general, low-quality conventional firecrackers can pose detrimental health impacts to children and older people during low planet boundary conditions with minimal wind velocity. •Metal bound PM2.5 contributes 22.7% to the total fine particulate matter load on Diwali day.•Arsenic, cadmium and lead concentration in ambient air exceeded permissible standards during Diwali.•Significant positive correlation (p-value<0.001) among Al, Ba, K, Mg and Sr, a typical signature of firecrackers found in this study.•Enrichment factor gave highly significant change in barium and strontium during Diwali days as compared to non-Diwali days.