How many sentences are correct?
$(1)$ $CNG$ burns most efficiently.
$(2)$ $CNG$ cannot be adulterated.
$(3)$ $CNG$ is cheaper than petrol and diesel.
$(4)$ In the $1990$s,Delhi ranked $4$th among the $41$ most polluted cities of the world.

$A$: High concentration of atmospheric $SO_2$ and $NO_x$ causes acid rain.
$R$: It causes damage to foliage and growing points of plants.

In acid rain,$SO_2$ accounts for approximately what percentage (in $, \%$)?

Match the following columns:

Column-$I$	Column-$II$
$(a)$ Environment Act	$(1)$ $1974$
$(b)$ The Air Act	$(2)$ $1987$
$(c)$ The Water Act	$(3)$ $1986$
$(d)$ Amendment in The Air Act	$(4)$ $1981$

Which of the following statements is/are correct?
$I.$ Chemical fertilizers cause pollution of water bodies as well as groundwater,besides getting stored in crop plants. Therefore,environmental scientists are pressing for a switch over to organic farming.
$II.$ Organic farming is a form of agriculture that relies on techniques such as crop rotation,green manure,compost,and biological pest control.

To which countries do developed countries export e-waste?