Excess nitrate in drinking water can cause

How much oxygen is added to the atmosphere annually at the end of the process of photosynthesis?

The water quality of a pond was analysed and its $BOD$ was found to be $4$. The pond has

Which of the following atmospheric pollutants is not emitted by vehicles?

In municipal sewage,$BOD$ values (in $ppm$) are

From the following,identify the reactions which are responsible for the depletion of the ozone layer.
$I. Cl\dot{O}_{(g)} + NO_{2_{(g)}} \rightarrow ClONO_{2_{(g)}}$
$II. CF_2Cl_{2_{(g)}} \xrightarrow{uv} \dot{Cl}_{(g)} + \dot{CF}_2Cl_{(g)}$
$III. \dot{Cl}_{(g)} + CH_{4_{(g)}} \rightarrow HCl_{(g)} + \dot{C}H_{3_{(g)}}$
$IV. \dot{Cl}_{(g)} + O_{3_{(g)}} \rightarrow Cl\dot{O}_{(g)} + O_{2_{(g)}}$
$V. Cl\dot{O}_{(g)} + O_{(g)} \rightarrow \dot{Cl}_{(g)} + O_{2_{(g)}}$