The eutrophication of water body results in ...... .

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

List-$I$	List-$II$
$a$. Biochemical oxygen demand	$i$. Oxidising mixture
$b$. Photochemical smog	$ii$. Stratospheric cloud
$c$. Classical smog	$iii$. Organic matter in water
$d$. Ozone layer depletion	$iv$. Reducing mixture

Choose the correct answer from the options given below:

How is ozone formed in photochemical smog?

Match the following:
| List-$I$ | List-$II$ |
| :--- | :--- |
| $A$. Methemoglobinemia | $I$. $1 \ ppm$ of dissolved oxygen in water |
| $B$. Kidney damage | $II$. $1000 \ ppb$ of lead in drinking water |
| $C$. Bones and teeth damage | $III$. $BOD$ of drinking water is $2 \ ppm$ |
| $D$. Growth of fish is stopped | $IV$. $2000 \ ppm$ of nitrates in drinking water |
| | $V$. $50 \ ppm$ of fluoride in drinking water |

Which of the following is harmful to calcium-containing structures and is responsible for causing cough and throat irritation in humans?

Which of the following statements is not true about classical smog?