Which gas is detected in the smoke produced due to the incomplete combustion of petrol or diesel?

Given below are two statements :
Statement $I$ : If $BOD$ is $4\,ppm$ and dissolved oxygen is $8\,ppm$,then it is a good quality water.
Statement $II$ : If the concentration of zinc and nitrate salts are $5\,ppm$ each,then it can be a good quality water.
In the light of the above statements,choose the most appropriate answer from the options given below :

The reaction that is $NOT$ involved in the ozone layer depletion mechanism in the stratosphere is

Which one of the following statements is not true?

Which of the following industries is the best source of increasing $CO$ levels in the atmosphere?

Identify the incorrect statement from the following.