Cow dung cakes (also known as uple) are mostly used as fuel in rural India.

1. Availability and Accessibility:
- Cow dung is easily available in rural areas as cows are commonly reared for milk and agricultural purposes.
- The accessibility of cow dung is high as it can be collected directly from the cowshed or village fields.

2. Traditional Practice:
- The use of cow dung as fuel has been a traditional practice in rural India for centuries.
- It has been passed down through generations as an effective and sustainable fuel source.

3. Cost-effective:
- Cow dung is a cost-effective fuel option as it is readily available and does not require additional expenses.
- In rural areas where income levels are relatively low, cow dung cakes provide an affordable source of energy for cooking and heating purposes.

4. Renewable and Sustainable:
- Cow dung is a renewable and sustainable fuel source as it is constantly produced by cows.
- It does not contribute to deforestation or environmental degradation, unlike other fuels like firewood or charcoal.

5. Cooking Efficiency:
- Cow dung cakes have a high energy content and burn efficiently, providing sufficient heat for cooking purposes.
- They are commonly used in traditional mud stoves or chulhas, which are designed to maximize heat retention and minimize fuel consumption.

6. Smokeless Cooking:
- When properly dried and used, cow dung cakes produce minimal smoke compared to other fuels like firewood or crop residues.
- This is beneficial for indoor air quality and reduces the risk of respiratory diseases among household members.

7. Fertilizer Benefits:
- After using cow dung cakes as fuel, the leftover ash can be used as a natural fertilizer in agricultural fields.
- This helps in enriching the soil with essential nutrients and improving crop yields.

In conclusion, cow dung cakes (uple) are widely used in rural India as a fuel source due to their availability, affordability, renewable nature, cooking efficiency, smokeless properties, and additional benefits as fertilizer.

Which among the following fuel is mostly used in rural ndia