Mumbai: The nation's ethanol blending programme is creating an unlikely winner: premium petrol.As E20 becomes the default fuel across India, a growing number of motorists are opting for higher-octane petrol amid concerns that E20 could hurt mileage and engine performance.However, premium petrol remains patchily available, with many fuel stations either not stocking it or offering it only sporadically, highlighting the weak economics of selling a low-volume fuel.Petrol pump dealers across the country told ET that enquiries for premium petrol have increased in recent months, with many customers willing to pay a 40-45% premium because they believe it delivers better mileage, smoother engine performance and improved pickup than regular E20 petrol.Lowering MaintenancePremium petrol, with its higher octane rating, is marketed for enhanced engine performance in vehicles designed to benefit from such fuel. It costs about ₹160 a litre in some markets, compared with around ₹112 a litre for regular petrol, although prices vary across states.Many also see the higher fuel cost as a worthwhile trade-off if it helps avoid what they perceive to be higher long-term maintenance costs.Premium petrol is regular fuel blended with additives or formulated with a higher octane rating to improve engine performance. It is designed to keep engines cleaner by reducing carbon deposits, lowering maintenance requirements and enhancing performance."The sales of premium petrol for all the oil companies range between 5% and 7% of the overall petrol sales," said a senior oil company executive. "Oil marketing companies target owners of premium four-wheelers and two-wheelers, and thus the fuel is available only in select cities and markets and select outlets."Oil companies reported 5-10% growth in premium petrol sales in the past quarter, albeit from a low base. "The demand for premium petrol has probably gone up as it contains specialised detergents and friction modifiers, which keep engine clean over a period of time. These help remove carbon deposits from critical parts of the vehicle," the oil company official added. Despite rising demand, availability remains limited as most fuel stations choose not to stock the product.Dealers said the economics do not justify the investment.A petrol pump owner in Pune said premium petrol accounts for less than 5% of sales at his outlet, making it difficult to justify the additional investment in storage infrastructure and inventory. "For such low demand, why should I block so much capital?" he said. "It doesn't make business sense."