Why was a little boy in a rickshaw coughing so much at the crossing?

The correct answer is option 'C', which states that the little boy was coughing due to a lot of smoke from vehicles. Let's explore this answer in detail.

Reasoning:
- The question mentions that the little boy was in a rickshaw at a crossing. This indicates that there were vehicles around, which could be a potential source of smoke.
- The fact that the boy was coughing excessively suggests that something in the environment was causing irritation to his respiratory system.
- Among the given options, the one that best explains this situation is the presence of smoke from vehicles. Vehicle exhaust contains pollutants such as carbon monoxide, nitrogen dioxide, and particulate matter, which can contribute to poor air quality and respiratory issues.

Detailed Explanation:

Smoke from Vehicles:
- Vehicles, especially those running on fossil fuels like petrol or diesel, produce exhaust fumes that contain harmful pollutants.
- These pollutants can include carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and particulate matter (PM2.5 and PM10).
- When these pollutants are released into the air, they can cause respiratory problems, particularly for individuals with sensitive airways such as children.
- Inhaling such pollutants can irritate the respiratory system, leading to coughing, wheezing, and difficulty in breathing.

Impact on the Little Boy:
- The little boy was likely exposed to a high concentration of vehicle exhaust due to his proximity to the crossing.
- As a result, his respiratory system became irritated, leading to excessive coughing.
- The smoke from vehicles may have caused inflammation in his airways, triggering a cough reflex as his body attempted to clear the irritants.
- The intensity of his coughing suggests that the smoke concentration was quite high, causing significant discomfort and distress.

Conclusion:
The little boy in the rickshaw was coughing so much at the crossing because there was a lot of smoke from vehicles. The pollutants present in vehicle exhaust can irritate the respiratory system, leading to coughing and other respiratory symptoms. It is essential to address air pollution and take measures to improve air quality to safeguard the health of individuals, especially children, who are more vulnerable to its effects.