The paper attempts to conducts comparative study between two largest public and private steel plants in India namely Steel Authority of India Limited (SAIL) and Tata Iron and Steel Company (TISCO) respectively regarding the issues on their economic and environmental performances. We collect the data on crude steel production and carbon dioxide emission for both plants from various annual reports of the plants and some primary sources over the period of 2001-2015 and employ the method of time series econometrics. Our empirical findings imply that production of crude steel significantly enhances the CO2 emission in both plants but degree of influence is notably greater in TISCO than in SAIL.