Which of the following is not a conventional source of energy?

Which of the following are correctly matched?
$I.$ Arsenic poisoning $-$ Black foot disease
$II.$ Secondary effluent treatment $-$ Biological process
$III.$ Pyrolysis $-$ Solid soil waste disposal
$IV.$ Tubifex $-$ Water pollution indicator
$V.$ Biomagnification $-$ Degradable pollutants

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

What is the biological concentration of $DDT$ in the body fat of Indian people?

$A$: Ecological sanitation is a sustainable system for handling human excreta.
$R$: It is a practical and hygienic method of using dry composting toilets.

Assertion : The concentration of methane in the atmosphere has more than doubled in the last $250$ years.
Reason : Wetlands and rice fields are the major sources of methane.