Most hazardous pollutant of automobile exhaust is

Which chemical compound caused the death of thousands of people in the Bhopal gas tragedy?

Which of the following gases causes pollution?

Why is $CNG$ considered a better fuel than diesel?
$(a)$ It cannot be adulterated.
$(b)$ It takes less time to fill the fuel tank.
$(c)$ It burns more efficiently.
$(d)$ It is cheaper.
$(e)$ It is less inflammable.
Choose the most appropriate answer from the options given below:

Which of the following is a weightless pollutant?

In the context of sound levels,$dB$ stands for .........