The Bhopal gas tragedy is associated with which of the following?

$A$ scrubber in the exhaust of a chemical industrial plant removes.......

Ahmed Khan's company developed a fine powder of recycled modified plastic called $..........$.

At what level does noise become harmful noise pollution?

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.

$A$ lake,which receives domestic sewage rich in organic waste,may result in: