According to the Central Pollution Control Board, particles that are responsible for causing great harm to human health are of diameter.

Options

A. 2 . 50 micrometers
B. 5 micrometers
C. 10 micrometers
D. 7.5 micrometers

Answer

To answer the question regarding the diameter of particles that are harmful to human health according to the Central Pollution Control Board, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the specific diameter of particles that are known to cause harm to human health.

2. **Reference the Central Pollution Control Board**: This organization provides guidelines and information regarding pollution and its effects on health.

3. **Identify the Relevant Information**: According to the Central Pollution Control Board and the National Council of Educational Research and Training (NCERT), particles that are particularly harmful to human health are those that have a diameter of less than or equal to 2.5 micrometers.

4. **Conclude the Answer**: Therefore, the particles that are responsible for causing great harm to human health are those with a diameter of **2.5 micrometers or less**.

### Final Answer:
The diameter of particles that are responsible for causing great harm to human health is **2.5 micrometers or less**.

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