Which among the following has the highest concentration of $PAN$?

Use of chlorofluorocarbons is not encouraged because

The primary pollutant that leads to photochemical smog is

Which one of the following statements is not true?

Which of the following statements is $NOT$ true according to the principles of green chemistry?

$A$ farmer is using pesticides in his field. He uses the produce from his field as food for fish. He is told that the fish are not fit for human consumption because large amounts of pesticides were found in the fish cells. How is this possible? Explain.