Public transport systems in today's world are observed as an opportunity to curb the carbon emissions resulting from commuting and thus help in combating climate change. This is because of their higher occupancy factor and lower per capita emissions compared to personal transport systems like cars, taxis etc. Of the several public transport systems available, some are more environment friendly when compared to others. Carbon footprint can be used as a tool for assessment of these transport systems and hence identifying and encouraging the use of sustainable transport mode.