Which of the following is an inexhaustible resource?

$BOD$ stands for:

Match the following important dates/events related to environmental legislation in India:
$(i)$ Air (Prevention and Control of Pollution) Act
$(ii)$ Environment (Protection) Act
$(iii)$ Water (Prevention and Control of Pollution) Act $(1974)$

Match the items in Column $A$ with those in Column $B$:
\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau

Column $A$	Column $B$
$(A)$ Catalytic converter	$(i)$ Particulate matter
$(B)$ Electrostatic precipitator	$(ii)$ Carbon monoxide and nitrogen oxides
$(C)$ Earmuffs	$(iii)$ High noise level
$(D)$ Landfills	$(iv)$ Solid waste

In this soil conservation method,several grasses are left out in the soil after the crop is harvested.

The Chernobyl tragedy occurred in