What is responsible for soil pollution?

If the $pH$ of water increases above ......,the effectiveness of chlorination in water is reduced.

Formation of photochemical smog involves the following reactions in which $A$,$B$,and $C$ are respectively:
$(i)$ $NO_2 \stackrel{h\nu}{\longrightarrow} A + B$
$(ii)$ $B + O_2 \rightarrow C$
$(iii)$ $A + C \rightarrow NO_2 + O_2$
Choose the correct answer from the options given below:

The photochemical smog does not generally contain.

Which gas among the following has the maximum global warming potential?

Excessive release of $CO_2$ into the atmosphere results in