Approach:

Introduction: Provide some background information on ethanol blending, such as what it is and why it is being promoted.

Body: Explain the advantages of ethanol blending in petrol and the challenges in achieving the target.

Conclusion: Summarise how the challenges can be addressed. 

Answer:

Ethanol blending is the practice of mixing ethanol with petrol to produce cleaner and cheaper fuel for vehicles. Ethanol is a biofuel derived from plant sources such as sugarcane, corn, and wheat. India has adopted ethanol blending as a strategy to lessen its reliance on crude oil imports, reduce carbon emissions, and increase farmers' incomes.

The Government of India has set a target of achieving 20% ethanol blending in petrol (E20) by 2025, which can save the country $4 billion per year.

Advantages of ethanol blending in petrol:

1. Reduces dependence on imported oil: India imports about 85% of its crude oil needs. By blending ethanol with petrol, India can reduce its dependence on imported oil and save foreign exchange. If India were to blend 20% ethanol into petrol, it would save about 2.2 million metric tonnes of oil per year.
2. Improves air quality: Ethanol burns more cleanly than petrol, which means that it produces fewer emissions of pollutants such as carbon monoxide, hydrocarbons, and particulate matter. This can help improve air quality and reduce the incidence of respiratory problems. The Indian Institute of Technology, Delhi, found that blending 10% ethanol in petrol can reduce carbon monoxide emissions by up to 30%.
3. Boosts the agricultural sector: Ethanol can be produced from a variety of agricultural feedstocks, such as sugarcane, corn, and wheat. This provides an opportunity to boost the agricultural sector and create jobs in rural areas. For example, the Indian government has estimated that blending 20% ethanol in petrol could create about 1 million jobs in the agricultural sector.
4. Increases octane rating: Ethanol has a higher octane rating than petrol, which means that it can improve engine performance and reduce the risk of engine knocking. This is especially important for high-performance vehicles. The octane rating of petrol is typically 87, while the octane rating of ethanol can be as high as 113.
5. Extends engine life: Ethanol can help clean the engine and remove deposits that can build up over time. This can help extend the life of the engine and improve fuel efficiency. A study by the University of California found that blending 10% ethanol in petrol can extend engine life by up to 20%.
6. Is a renewable resource: Ethanol can be produced from renewable sources, such as sugarcane and corn. This means that it is a sustainable fuel that does not contribute to climate change. The production of ethanol from sugarcane generates about 30% less greenhouse gas emissions than the production of petrol.

Challenges in achieving the target:

1. Availability of ethanol: India currently produces about 3 billion litres of ethanol per year, but this is not enough to meet the demand for 20% blending.
2. Compatibility with vehicle engines: Some older engines may not be able to run on ethanol blends, and some newer engines may require modifications to be compatible with ethanol.
3. Cost of ethanol blending: Ethanol is currently more expensive than petrol. The prices of ethanol produced in India are higher in comparison to global players, since the cost of raw materials--that is, sugarcane and food grains--are fixed by the government to support farmers. So blending ethanol with petrol can increase the cost of fuel.
4. Infrastructure: There are not enough ethanol blending plants, and the distribution network for ethanol is not as well-developed as the distribution network for petrol.
5. Consumer acceptance: Some consumers may be hesitant to use ethanol blends because they are not familiar with them or they are concerned about the performance of their vehicles on ethanol blends. For example: There is an estimated loss of 6-7% fuel efficiency for 4-wheelers operating on E20 though designed for petrol or calibrated for E10.

Achieving 20% ethanol blending in petrol by 2030 is a challenging but feasible goal for India. Some of the key steps to address the challenges are: increasing the production and availability of ethanol from various feedstocks, such as sugarcane, corn, rice and biomass; creating a robust supply chain and distribution network for ethanol blending across the country, etc. By overcoming these challenges, India can reduce its dependence on imported oil, lower its carbon emissions and promote sustainable development.