Identify the incorrect statement.

Match the Column-$I$ with Column-$II$:

Column-$I$	Column-$II$
$(a)$. Pyrolysis	$(i)$. Methaemoglobinemia
$(b)$. Carbon monoxide	$(ii)$. Chronic exposure to arsenic
$(c)$. Blue baby syndrome	$(iii)$. Asphyxia and giddiness
$(d)$. Black foot disease	$(iv)$. Disposal of hospital waste

If an agricultural field is liberally irrigated for a prolonged period of time,it is likely to face the problem of:

Which of the following organisms is likely to have the highest concentration of $D.D.T.$ in its body?

In India,the most commonly used pesticide $BHC$ is

In a pond near a village,a large number of fish suddenly die. Which of the following could be the reason for this?
$(a)$ Large amounts of urea and phosphate are used as fertilizers in nearby fields.
$(b)$ $DDT$ was sprayed in the entire area.
$(c)$ The pond water has become green and dirty.
$(d)$ The population of phytoplankton in the pond has decreased,reducing the photosynthetic capacity.
Which two of the above reasons are responsible?