A study conducted by Nielsen for the ministry's Petroleum Planning and Analysis Cell (PPAC) found that private cars consumed 13.15 per cent of the 69.08 million tonne diesel consumed in the country in 2012-13.
Commercial vehicles used another 8.94 per cent and three-wheelers, a further 6.39 per cent.
Commercial vehicles such as trucks however constituted the largest user base of diesel at 28.25 per cent, the study said, adding that 70 per cent of the diesel was being used in the transport sector.
Agriculture tractors and pumps used 13 per cent of the diesel.
Industries and electricity generators consumed almost 9 per cent diesel, while mobile towers used 1.54 per cent.
The study found that 99.6 per cent of petrol is consumed in the transport sector alone.
"Of this, majority consumption of 61.42 per cent is accounted for by two-wheelers while cars use 34.33 per cent, followed by 3-wheelers at 2.34 per cent," an official statement said.
It was also revealed that in Odisha, Bihar and Rajasthan, petrol consumption by two-wheelers exceeds 70 per cent.
The consumption by three-wheelers is very low in states like Delhi, Haryana, Gujarat and Odisha, where consumers have shifted to CNG or diesel.
"While pricing of petrol was deregulated, diesel prices are still being regulated, with subsidy running at Rs 8.47 per litre currently," the statement said.
The total subsidy on diesel during 2012-13 was Rs 92,061 crore, constituting 57.2 per cent of the total fuel subsidy.
"The question as to where the Diesel is getting consumed is very relevant in this context," it said.
The statement added: "Based on sector-wise consumption pattern of diesel, it would mean that of the total under- recovery of Rs 92,061 crore on account of diesel during 2012- 13, about Rs 12,100 crore went to owners of private cars and utility vehicles, about Rs 8,200 crore to commercial cars and SUVs, about Rs 26,000 crore to trucks, about Rs 8,800 crore to buses, about Rs 12,000 crore to agriculture sector and about Rs 15,600 crore to other sectors."