Which of the following is the main factor of water pollution?

Options

A. Smoke
B. Industrial waste
C. Detergent
D. Ammonia

Answer

To determine the main factor of water pollution from the given options, we can analyze each option systematically:

1. **Smoke**: While smoke can contribute to air pollution and indirectly affect water bodies through acid rain, it is not a direct cause of water pollution.

2. **Industrial Waste**: This is a significant contributor to water pollution. Industrial processes often release harmful chemicals and waste products directly into rivers, lakes, and oceans. These wastes can include heavy metals, toxins, and other pollutants that severely impact aquatic life and water quality.

3. **Detergent**: Detergents can contribute to water pollution, especially in terms of causing eutrophication in water bodies. However, they are not the primary factor when compared to industrial waste.

4. **Ammonia**: Ammonia can be a pollutant found in agricultural runoff and wastewater, but it is also not the main factor of water pollution on a larger scale compared to industrial waste.

Based on this analysis, the main factor of water pollution is **industrial waste**.

### Step-by-Step Solution:
1. **Identify the options**: Smoke, industrial waste, detergent, and ammonia.
2. **Evaluate each option**:
- Smoke: Not a direct cause of water pollution.
- Industrial Waste: Major contributor to water pollution.
- Detergent: Contributes to pollution but not the primary factor.
- Ammonia: Present in some pollutants but not the main factor.
3. **Conclude**: The primary factor of water pollution is industrial waste.