Which of the following will help in controlling air pollution?
I. Use of bicycles instead of cars for covering short distances.
II. Spraying pesticides in agricultural fields to control pests.
III. Use of unleaded petrol and smokeless fuels like CNG, LPG, etc.
IV. Use of CFCs in refrigeration and air conditioning.

Options

A. I and III only
B. II and III only
C. I and IV only
D. II and IV only

Explanation

To determine which of the given options will help in controlling air pollution, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Statement I: Use of bicycles instead of cars for covering short distances.**
- **Analysis:** Bicycles do not emit harmful gases like carbon monoxide or carbon dioxide, which are released by cars. By using bicycles, we reduce the number of cars on the road, leading to less air pollution.
- **Conclusion:** This statement is true and helps in controlling air pollution.

2. **Statement II: Spraying pesticides in agricultural fields to control pests.**
- **Analysis:** While pesticides help in controlling pests, they can also release harmful chemicals into the air. These chemicals can contribute to air pollution and can be harmful to both human health and the environment.
- **Conclusion:** This statement does not help in controlling air pollution.

3. **Statement III: Use of unleaded petrol and smokeless fuels like CNG, LPG, etc.**
- **Analysis:** Unleaded petrol and smokeless fuels produce fewer harmful emissions compared to traditional fuels. Using these fuels reduces the release of toxic gases into the atmosphere, thereby helping to control air pollution.
- **Conclusion:** This statement is true and helps in controlling air pollution.

4. **Statement IV: Use of CFCs in refrigeration and air conditioning.**
- **Analysis:** Chlorofluorocarbons (CFCs) are known to deplete the ozone layer and can contribute to air pollution. Their use is being phased out due to their harmful effects on the environment.
- **Conclusion:** This statement does not help in controlling air pollution.

### Final Conclusion:
Based on the analysis, the statements that help in controlling air pollution are:
- I. Use of bicycles instead of cars for covering short distances.
- III. Use of unleaded petrol and smokeless fuels like CNG, LPG, etc.

Thus, the correct answer is **I and III only**.