Assessment of emission reduction potential of Mumbai metro rail

Abstract

Abstract First line of Mumbai metro rail system was implemented in 2014 for reduction in traffic congestion and to provide a better connectivity between eastern and western suburbs of Mumbai metropolitan region (MMR). Apart from connectivity, reduction in greenhouse gases (GHG), gaseous pollutants like carbon monoxide (CO), hydrocarbon (HC), oxides of nitrogen (NOx), particulate matter (PM) were the main goal behind implementation of metro. In this study, we analyse the reduction in carbon dioxide (CO2) and other emissions due to shift of commuters to metro from other mode of transportation. In addition, monetary savings in travel time is also determined as travel time is the main attraction for using metro. The emissions were estimated through modal shift of passengers by converting the ridership data to equivalent number of vehicles on road. Our analysis shows modal shift resulted in reduction of 22.7 tonne of CO2 emission per day but ∼75.6 tonne of CO2 is emitted per day from the electricity consumed in metro operation. However, pollutants like CO, HC were reduced by metro and high savings in value of travel time was obtained. Overall, the results illustrate that so far the metro rail is yet to achieve reduction in greenhouse gases (GHG) emissions since a major shift occurred from public transportation. However, with increase in ridership metro rail can achieve the benefits in reduction of emissions.