$.........$ is an undesirable,high-intensity sound.

Nitrogen oxides are produced from the emissions of automobiles and power stations,which are a source of fine particulate matter in the air,leading to the formation of .....

$A$: $Euro-II$ norms were framed to reduce the content of $CO$ and aromatic compounds from fuels.
$R$: These compounds lead to reduced visibility and carboxyhemoglobin formation.

The main air pollutant is:

Two lakes,$A$ and $B$ are identical in all aspects except that lake $A$ has higher temperature. Which of the following is true?

Select the correct option regarding algal bloom.
$I-$ Excessive growth of planktonic algae occurs due to the presence of high amounts of nutrients in water bodies.
$II-$ Algal bloom imparts a distinct color to the water bodies.
$III-$ Algal bloom causes deterioration of water quality and fish mortality.
$IV-$ All bloom-forming algae are highly toxic to humans and animals.