This paper examines the impact of urbanization on CO₂ emissions in developing countries. It analyzes how urbanization affects emissions, considering population as a variable rather than assuming a unitary elasticity of emissions with respect to population growth. The study covers data from 1975 to 2005 for different income groups of countries. The results show that the impact of population growth on emissions is above unity, with slightly different effects for upper, middle, and low-income countries. Urbanization has a different impact on emissions for low and lower-middle-income countries and upper-middle-income countries. For low-income countries, the elasticity of emissions-urbanization is higher than unity, while for upper-middle-income countries, it is negative. The study highlights the heterogeneous impact of urbanization on CO₂ emissions and suggests that future climate change policies should consider these differences. The paper also discusses the role of affluence, energy efficiency, and industrial activity in influencing emissions. The findings indicate that urbanization can have a negative effect on emissions in developed countries, while in developing countries, it may have a positive effect. The study uses econometric methods to decompose emissions into scale, composition, and technique effects, providing insights into the factors driving changes in pollution. The results suggest that technical progress and energy efficiency play important roles in reducing emissions. The paper concludes that urbanization can contribute to reduced environmental damage once it reaches a certain level, and that policymakers should consider the potential benefits of urbanization in long-term sustainability efforts.This paper examines the impact of urbanization on CO₂ emissions in developing countries. It analyzes how urbanization affects emissions, considering population as a variable rather than assuming a unitary elasticity of emissions with respect to population growth. The study covers data from 1975 to 2005 for different income groups of countries. The results show that the impact of population growth on emissions is above unity, with slightly different effects for upper, middle, and low-income countries. Urbanization has a different impact on emissions for low and lower-middle-income countries and upper-middle-income countries. For low-income countries, the elasticity of emissions-urbanization is higher than unity, while for upper-middle-income countries, it is negative. The study highlights the heterogeneous impact of urbanization on CO₂ emissions and suggests that future climate change policies should consider these differences. The paper also discusses the role of affluence, energy efficiency, and industrial activity in influencing emissions. The findings indicate that urbanization can have a negative effect on emissions in developed countries, while in developing countries, it may have a positive effect. The study uses econometric methods to decompose emissions into scale, composition, and technique effects, providing insights into the factors driving changes in pollution. The results suggest that technical progress and energy efficiency play important roles in reducing emissions. The paper concludes that urbanization can contribute to reduced environmental damage once it reaches a certain level, and that policymakers should consider the potential benefits of urbanization in long-term sustainability efforts.