Mention the harmful effect of ultra violet radiations.

Given below are two statements :-
Statement $I :$ The value of the parameter "Biochemical Oxygen Demand $(BOD)$" is important for survival of aquatic life.
Statement $II :$ The optimum value of $BOD$ is $6.5 \ ppm$.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which of the following statements is $NOT$ in accordance with the fundamental principles of Green Chemistry?

Match List-$I$ with List-$II$ :

List-$I$ (Species)	List-$II$ (Maximum allowed concentration in ppm in drinking water)
$A$. $F^{-}$	$I$. $< 50 \, ppm$
$B$. $SO_{4}^{2-}$	$II$. $< 5 \, ppm$
$C$. $NO_{3}^{-}$	$III$. $< 2 \, ppm$
$D$. $Zn$	$IV$. $< 500 \, ppm$

Water filled in two glasses $A$ and $B$ have $BOD$ values of $10$ and $20$ respectively. The correct statement regarding them is:

How can photochemical smog be controlled?