Which one of the following is not a bioindicator of water pollution?

$E$-waste are buried in ...$A$... or ...$B$.... Complete the given statement by choosing appropriate option for $A$ and $B$.

What happens when sewage is discharged into a river?

$A$ lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this:
$1.$ Lots of urea and phosphate fertilizer were used in the crops in the vicinity.
$2.$ The area was sprayed with $DDT$ by an aircraft.
$3.$ The lake water turned green and stinky.
$4.$ Phytoplankton populations in the lake declined initially,thereby greatly reducing photosynthesis.
Which two of the above were the main causes of fish mortality in the lake?

Phosphate pollution is caused by

In which year did the Government of India introduce the concept of Joint Forest Management $(JFM)$?