This study looks at the short- and long-term effects of fossil fuels, renewable energy, and nuclear energy on CO2 emissions in the South Asian Association for Regional Cooperation (SAARC) countries from 1982 to 2021. We assess the impacts of SAARC’s current and anticipated use of nuclear, fossil, and alternative energies by testing the environmental Kuznets curve (EKC) hypothesis. The study applied the second-generation unit root test, cointegration test, and the newly introduced AMG technique to handle the presence of cross-sectional dependence. The results indicate that EKC does not hold in SAARC, and a U-shaped quadratic link exists between GDP and environmental pollution. The findings also reveal that the environmental pollution in the SAARC is caused by fossil fuel, whereas using renewable (REN) and nuclear energy can cut long-term pollution. While renewable energy is critical to minimizing environmental deterioration in SAARC, empirical findings also show that more than rising national wealth is needed to meet environmental demands. According to the results of this study, SAARC countries should take the lead in achieving sustainable growth and the efficient use of clean energy.