Over $10 \ ppm$ fluoride causes

Write down the reactions involved during the formation of photochemical smog.

What are biodegradable and non-biodegradable pollutants?

Identify the air pollutant which in high concentration leads to stiffness of flower buds?

Given below are two statements:
Statement $I:$ Classical smog occurs in cool humid climate. It is a reducing mixture of smoke,fog and sulphur dioxide.
Statement $II:$ Photochemical smog has components,ozone,nitric oxide,acrolein,formaldehyde,$PAN$ etc.
In the light of above statements,choose the most appropriate answer from the options given below:

Match the following:

List-$I$ (Pollutant concentration limit in water)	List-$II$ (Effect)
$A. Pb > 50 \ ppb$	$I. \text{Liver damage}$
$B. SO_4^{2-} > 500 \ ppm$	$II. \text{Laxative effect}$
$C. NO_3^{-} > 50 \ ppm$	$III. \text{Blue baby syndrome}$
$D. F^{-} > 2 \ ppm$	$IV. \text{Brown mottling of teeth}$

The correct answer is