Which of the following radiations is non-ionizing?

Consider the following statements:
$I.$ Algal blooms are formed by free-floating algae.
$II.$ Algal blooms cause fish mortality and deterioration of water quality.
$III.$ Water hyacinth, the world's most problematic aquatic weed, is also called 'Terror of Bengal'.
Which of the statements given above are correct about algal blooms?

$A$: Taj Mahal is being destroyed by $SO_2$ coming from Mathura refinery.
$R$: This converts $CaCO_3$ into unstable calcium sulphate.

$A$ - 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.

Pollution is not caused by

Why is the use of unleaded petrol recommended for motor vehicles equipped with catalytic converters?