Transport Emissions and India’s Diesel Mystery

The purpose of this research is to determine if the road transport sector in India is really showing signs of a decoupling of energy consumption and travel demand, or if there are inconsistencies in the official estimates, which would therefore not be reflective of realities on the ground. Based on the detailed analysis, the use of top-down data on fuel consumption in the road transport sector in India may have led to serious errors. There is a significant gap between what government statistics suggest and what bottom-up estimates indicate.

There is wide variation among the bottom-up emissions estimates. The predominant cause of variation is diesel consumption. The total number of motor vehicles and the total distance travelled are the key variables in determining total fuel consumption and carbon emissions. Unfortunately, until this information is collected and updated annually, the quality of the bottom-up measurements cannot be improved.

The trends and scenarios in this research explain and establish the need to prioritize diesel vehicle data collection to improve bottom-up modeling. Improving diesel consumption data will provide quick wins in reducing variation among bottom-up modeling estimates and provide better insights on energy efficiency in the transport sector. In the long term, the establishment of national transport household surveys as a supplement to the national census should be prioritized. Clearly, mobility for people and freight in a country with 1.2 billion people cannot be planned adequately without sufficient resources allocated to data generation and analysis. Analysis of top-down and bottom-up data in India provides interesting perspectives on the quality of both top-down and bottom-up quantifications.