The smog is essentially caused by the presence of

Options

A. `O_(3) and N_(2)`
B. `O_(2) and N_(2)`
C. Oxides of sulphur and `N_(2)`
D. `O_(2) and O_(3)`

Answer

To solve the question regarding the causes of smog, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Smog**: Smog is a type of air pollution that combines smoke and fog. It typically occurs in urban areas where there is a high concentration of pollutants.

2. **Identifying Components of Smog**: The main components that contribute to the formation of smog include various pollutants such as volatile organic compounds (VOCs), oxides of nitrogen (NOx), and oxides of sulfur (SOx).

3. **Role of Pollutants**:
- **Volatile Organic Compounds (VOCs)**: These are emitted from burning fossil fuels and other industrial activities. They react in the atmosphere to form secondary pollutants.
- **Oxides of Nitrogen (NOx)**: These are produced from vehicle emissions and industrial processes. They play a significant role in the formation of ozone at ground level.
- **Oxides of Sulfur (SOx)**: These are primarily produced from burning coal and oil, and they contribute to the formation of acid rain and smog.

4. **Formation of Ozone**: In the presence of sunlight, VOCs and NOx can react to form ozone (O3), which is a major component of smog.

5. **Conclusion**: Based on the above points, the presence of oxides of sulfur and nitrogen is essential for the formation of smog. Therefore, the correct answer to the question is that smog is essentially caused by the presence of **oxides of sulfur and nitrogen**.

### Final Answer:
The smog is essentially caused by the presence of **oxides of sulfur and nitrogen**.

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