A proposed ban by 2027 on four-wheeler diesel vehicles in Indian cities with a population of over 1mn and in highly polluted towns could make limited contribution to cutting greenhouse gas (GHG) emissions.
The ban, proposed in a report by the Energy Transition Advisory Committee (Etac) of the Indian oil ministry, will not contribute to cutting emissions significantly given the continuing fall in the share of diesel vehicles in India's total vehicle sales.
The report, whose recommendations the oil ministry are yet to accept it said on 10 May, also recommends several other measures to aid India's 2070 net zero goal, including boosting the share of electric vehicles (EVs) in the total number of vehicles, as well as a progressive switch to gasoline and biodiesel blending in transport fuels.
But the fall in emissions is unlikely to come mainly from switching four-wheeler vehicles to cleaner fuels. Four-wheeler full diesel vehicle sales have been on in falling trend since at least 2014. But sales of four-wheeler full gasoline vehicles almost doubled over the same period (see table). The share of full diesel vehicles in total vehicle sales fell to under 11pc in the April 2022-March 2023 fiscal year from just over 14pc in 2014-15, data from government portal Vahan show.
The drop in the share of full diesel vehicles in total four-wheeler sales accelerated after the government deregulated fuel prices in late 2014 and ended subsidies, likely because of a narrowing spread between retail gasoline and diesel prices. Retail gasoline prices were 96.72 rupees/litre in Delhi on 9 May compared with Rs89.62/l for diesel, a difference of Rs7.10/l. Gasoline prices were Rs72.26/l in Delhi on 1 April 2014 compared with Rs55.49/l for diesel, a spread of Rs16.77/l.
India also launched a national vehicle scrapping policy in August 2021, aimed at phasing out unfit and polluting vehicles. The policy deregisters privately-owned cars older than 20 years and commercial vehicles older than 15 years.
Indian carbon dioxide (CO2) emissions rose to 2.7bn t in 2019, the third-highest in the world, from 900mn t in 2000. But around 1.2bn t of emissions came from the power sector in 2019 compared with only 300mn t from the road. CO2 emissions are lower in diesel engines compared with gasoline-powered vehicles. But diesel engines emit more nitrous oxide and particulate matter, controlling which increases the cost of production and discouraging auto manufacturers.
Auto producers shun diesel
Some automobile manufacturers stopped selling diesel vehicles after the new Bharat Stage VI (BS-6) regulations came into effect from 1 April 2020, likely because of the cost of meeting emissions regulations for diesel. BS-6 regulations reduced the limit for particulate matter and nitrogen oxide emissions.
Indian diesel demand from the transportation sector was 80pc of total diesel demand of 73mn t (1.49mn b/d) in 2021, up from 70pc in 2013, according to the Etac report. This was led by a surge in diesel demand from the commercial trucks segment, which doubled from around 28pc of total consumption in 2013 to 55pc in 2021. But the share of demand from four-wheeler taxis fell from 9pc in 2013 to 3pc in 2021, while the share of privately-owned vehicles fell from 13pc to 12pc over the same period. The total share of passenger vehicles in diesel demand fell to less than 17pc in 2021 from 29pc in 2013.
India is also moving away from full diesel and full gasoline vehicles with the gasoline blending policy and target for 5pc biodiesel blending in diesel by 2030. The national Ethanol Blended Petrol (EBP) programme has set a target of 20pc ethanol blending in gasoline by 2025. The country is on target to achieve 12pc ethanol blending in gasoline during the December 2022-November 2023 ethanol season, with 11.43pc already achieved.
The Etac report also recommends that four-wheelers be shifted to 50pc electric and 50pc EBP, with a focus on transition to EVs within 15 years. But four-wheeler EVs comprised just 4pc of all EV sales in India during 2022-23, stable from a year earlier, with two-wheelers comprising 62pc of sales in both years. The two and three-wheelers, including those using diesel and gasoline, comprised 76pc of all vehicle sales in 2022-23, stable from a year earlier, according to data from the Federation of Automobile Dealers Associations.
The Etac report recommends a long-term shift to mass transit systems such as railways.
Indian personal vehicle ownership was 20 vehicles per 1,000 people in 2013, according to the IEA. But this is projected to rise to 175 per 1,000 people by 2040, which could hinder any move towards mass transit systems and the resultant shift away from fossil fuel consumption in the transport sector.
| India diesel vehicle sales | |||
| 2014-15 | 2022-23 | ± % | |
| 4-wheeler diesel sales | 1,145,845 | 652,438 | -43 |
| 4-wheeler gasoline sales | 1,117,693 | 2,183,528 | 95 |
| % diesel to gasoline | 103 | 30 | -70 |
| Total 4-wheeler vehicle sales | 2,454,327 | 3,463,862 | 41 |
| % diesel to total 4-wheeler sales | 47 | 19 | -60 |
| Total diesel vehicle sales | 2,823,086 | 2,423,942 | -14 |
| Total vehicle sales | 19,391,865 | 22,274,832 | 15 |
| % diesel to total | 15 | 11 | -25 |
| Source: Vahan |
