India's wealthy can be strangely stingy. BMW became the country's top-selling luxury car brand last year after less than three years in the country by giving consumers a choice of different sizes of luxury sedans, SUVs and even convertibles, said Peter Kronschnabl, president of BMW India.

However, one of the most important options for many Indians that end up buying BMWs is a diesel-powered engine. Around 40% of BMW models available in India are diesel powered .

While...