Which of the following is the most significant air pollutant in modern times?

Given below are two statements:
Statement $I$: An allotrope of oxygen is an important intermediate in the formation of reducing smog.
Statement $II$: Gases such as oxides of nitrogen and sulphur present in the troposphere contribute to the formation of photochemical smog.
In the light of the above statements,choose the correct answer from the options given below:

What kind of steps should be taken to control environmental pollution?

Green chemistry means such reactions which

The living organisms or the surroundings of the earth's composition are known as .....

The possibility of photochemical smog formation is more at