Air Pollution produced from automobiles has become one of the most critical problems of environmental concern and likely to increase as vehicle population is assumed to grow approximately by 1300 million by the year 2030. In India, automobiles will have to meet the BS-VI emission standards to reduce vehicular pollution that impacts on environment and human health. These norms impose various restrictions on emissions of exhaust gases like NOx, HCs, particulate matter. Many recent exhaust control devices are being developed to meet the required needs. Therefore, the present study aims to reduce CO2 emissions generated in SI engine automobiles using activated carbon/calcite in a muffler. The backpressure parameter of the muffler affects the efficiency of an internal combustion engine. The porosity and diameter of the inner tube of the muffler has a prominent effect on backpressure. Therefore, the muffler with 48, and 60 holes, respectively and 1mm and 2mm diameter, respectively on a perforated tube have been investigated. The result shows that the concentration of CO2 and back pressure is greatly reduced by increasing porosity and diameter, respectively of the tube. Thus, an environmentally friendly and efficient muffler is modeled and simulated.