Pollutant which reduces oxygen carrying capacity of haemoglobin, leading to suffocation or death is

Options

A. carbon monoxide
B. sulphur dioxide
C. ozone
D. nitric oxide.

Explanation

### Step-by-Step Solution:

1. **Understanding Hemoglobin**: Hemoglobin is a protein found in red blood cells that binds to oxygen and transports it throughout the body. It is essential for delivering oxygen to tissues and organs.

2. **Identifying Pollutants**: Some pollutants can interfere with the ability of hemoglobin to carry oxygen. These pollutants can bind to hemoglobin instead of oxygen, leading to a decrease in oxygen levels in the blood.

3. **Competitive Inhibition**: The process by which a pollutant binds to hemoglobin instead of oxygen is known as competitive inhibition. In this case, the pollutant competes with oxygen for binding sites on hemoglobin.

4. **Recognizing the Harmful Pollutant**: The primary pollutant that reduces the oxygen-carrying capacity of hemoglobin is carbon monoxide (CO). Carbon monoxide binds to hemoglobin more effectively than oxygen does, leading to reduced oxygen transport in the body.

5. **Consequences of Carbon Monoxide Exposure**: When carbon monoxide binds to hemoglobin, it leads to symptoms such as suffocation, breathing difficulties, and can ultimately result in death if exposure is prolonged.

6. **Conclusion**: Therefore, the pollutant that reduces the oxygen-carrying capacity of hemoglobin, leading to suffocation or death, is carbon monoxide.

### Final Answer:
The pollutant which reduces the oxygen-carrying capacity of hemoglobin, leading to suffocation or death, is **carbon monoxide**.

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