What is polluted by chemically synthesized pesticides?

Which measures can be taken to control noise pollution?
$I-$ Use of sound-absorbent materials or mufflers in industries.
$II-$ Creating horn-free zones around hospitals and schools.
$III-$ Setting permissible sound levels for firecrackers and loud speakers.
$IV-$ Restricting the use of loudspeakers after a certain time.

Noise is:

Which pollutant from motor-car exhaust causes a mental disease?

Some toxic substances present in industrial waste water can undergo $.........$ in the aquatic food chain.

Which of the following is a pollution-related disorder?