What is used to remove particulate matter from industrial exhaust?

Which steps were taken in Delhi to reduce pollution from vehicles?
$I-$ Phasing out of old vehicles
$II -$ Use of leaded petrol
$III -$ Use of low-sulphur petrol and diesel
$IV -$ Use of catalytic converters in vehicles
$V -$ Application of stringent pollution level norms for vehicles

$DDT$ is a

The excessive discharge of fertilizers into water bodies results in

The phenomenon in which nutrient enrichment of a water body supports a dense growth of one or many organisms but decreases the species diversity is called:

What do you understand by biomagnification? Explain it.