The possibility of photochemical smog formation will be minimum at

The correct set of species responsible for the photochemical smog is

Which of the following is significant for water pollution?

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:

List gases which are responsible for the greenhouse effect.

Which of the following is a sink for $CO$?