Why CNG is called clean fuel?

Explanation

### Step-by-Step Solution:

1. **Definition of CNG**: CNG stands for Compressed Natural Gas. It primarily consists of methane (CH4), which is a hydrocarbon.

2. **Composition of CNG**: The main component of CNG is methane, along with small amounts of nitrogen (N2), carbon dioxide (CO2), propane (C3H8), and ethane (C2H6). However, methane is the dominant component.

3. **Comparison with Fossil Fuels**: Traditional fossil fuels, such as petrol and diesel, contain various impurities including nitrogen and sulfur. When these fuels are burned, they produce harmful emissions like nitrogen dioxide (NO2) and sulfur dioxide (SO2), which contribute to air pollution.

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