China and India are the world's largest developing economies and also two of the most populous countries. China, which now has more than 1.3 billion people, is expected to grow to more than 1.4 billion by 2050, and India with a population of 1 billion will overtake China to be the most populous country with about 1.6 billion population. These two countries are home to 37% of the world's population today. In addition, China and India have achieved notable success in their economic development characterised by a high rate of gross domestic product (GDP) growth in the last two decades. Together the two countries account already for almost a fifth of world GDP. The most direct and significant result of economic growth in India and China is the amazing improvement in quality of life (or at least spending power) for an increasing share of the population. The populations of both the countries have experienced a transition from 'poverty' to 'adequate food and clothing'; today growing parts of the population are getting closer to 'well to do lifestyles'. These segments of the society are not satisfied any more with enough food and clothes, but are also eager to obtain a quality life of high nutrient food, comfortable living, health care and other quality services. The theme of this paper is to analyse how the major drivers contributed to the environmental consequences in the past, and to take a forward look at the environmental impacts of these driving forces in China and India. The paper identifies population, affluence and technology to be the major driving forces in environmental pollution for these two countries then applies the simple equation of Impact=Population×Affluence×Technology, or I=PAT to evaluate the effects of changes in these drivers on CO2 emissions.