In its push to reduce the fiscal deficit, India has reduced fuel subsidies. That, plus rising prices, is pushing the cost of vehicle ownership up by 3 to 5 percent, the auto group said.
The International Monetary Fund on Tuesday slashed its growth forecast for India's economy to 4.9 percent from 6.1 percent.
New Delhi has belatedly pushed through measures intended to stoke growth and reassure investors, including opening retailing and airlines to greater foreign investment.
Standard and Poor's said Wednesday that India still faces a one in three chance of a sovereign credit downgrade in the next 24 months, despite the flurry of reform.