Give scientific reasons: The use of $CNG$ is more advantageous than the use of petrol.

Indicator plants which can be used to indicate atmospheric pollution by $SO_2$ are

Explain pollution caused by automobiles and how the use of a catalytic converter in them reduces pollution.

Which is the most widely used insecticide in the world?

$A$ - Micro-organisms involved in the biodegradation of organic matter in the receiving water body consume a lot of oxygen,and as a result,there is a sharp decline in dissolved oxygen in the stream from the point of sewage discharge.
$R$ - $BOD$ decreases when the dissolved oxygen amount decreases in water.

For $3$ wheelers vehicles,which emission norm was implemented throughout the country since October $2010$?