The consequence of global warming may be the following:

Assertion : Ozone is destroyed by $CFCs$ in the upper stratosphere. Reason : Ozone holes increase the amount of $UV$ radiation reaching the earth.

Match the pollutant in List-$I$ with its maximum permissible limit in drinking water given in List-$II$.

List-$I$	List-$II$
$(A)$ Lead	$(I)$ $500 \text{ ppm}$
$(B)$ Sulphate	$(II)$ $50 \text{ ppm}$
$(C)$ Nitrate	$(III)$ $50 \text{ ppb}$

For dry cleaning of clothes,instead of tetrachloroethene,which is carcinogenic in nature,which of the following solvents can be used?

Fill in the blanks:
$(1)$ Hydrocarbon compounds are made from ........ and ........ .
$(2)$ ........ has a capacity to stop the flow of oxygen.
$(3)$ ........ is formed by attaching carbon monoxide with hemoglobin in blood.

$A$ water sample is reported to be highly polluted if the $BOD$ (Biological Oxygen Demand) value of the sample becomes: