Background <p>Environmental and indoor air pollution causes respiratory infection related morbidity and mortality. Hence, the study tries to explore the relationship of environmental PM_2.5 and indoor air pollution with the prevalence of Lower Respiratory Infection (LRIs) related neonatal (NMR) and under-five child mortality (U5MR) in India.</p> Materials &amp; methods <p>The study extracted NMR, U5MR, PM_2.5 and other environmental data from Global Burden of Disease (GBD) database (2021), and collected state level indoor air pollution and socioeconomic information of the child, mothers, and community from the fifth round of the National Family Health Survey (NFHS-5), 2019–21 dataset. The investigation employed join point regression analysis, Ordinary Least Square (OLS) regression models and spatial analysis technique to establish the relationship between PM_2.5, indoor pollution and NMR or U5MR caused by LRIs in India.</p> Results <p>The trend analysis indicates that NMR and U5MR declined significantly by 66% and 74%, respectively from 1990 to 2021 in India. OLS regression models highlighted significantly positive association of PM_2.5 pollution, indoor air pollution, unclean cooking fuel use, and absence of ventilation and separate kitchen in the houses on the prevalence of NMR and U5MR attributed to LRIs in India. Besides, spatial analysis reveals significant concentration and spatial association of PM_2.5 and NMR or U5MR in some northern, and central Indian states like Rajasthan, Haryana, Uttar Pradesh, Madhya Pradesh, and Bihar.</p> Conclusion <p>The study revealed that elevated PM_2.5 concentrations are likely linked to contributing factors for higher child mortality, particularly in the Indo-Gangetic Plain (IGP) region. To address this issue, the study suggests increasing public awareness and implementing targeted policies to reduce neonatal and under-five mortality across India.</p> Graphical Abstract <p></p>