Which chemical compound caused the death of thousands of people in the Bhopal gas tragedy?

Which of the following causes degradation of $RBCs$?

$A$ lake with an inflow of domestic sewage rich in organic waste may result in:

Delhi is one of the most polluted cities of the world. Which of the following steps were taken by the government to reduce vehicular pollution in Delhi?
$I.$ Phasing out of old vehicles
$II.$ Use of unleaded petrol
$III.$ Use of low sulphur petrol and diesel
$IV.$ Use of catalytic converters in vehicles
$V.$ Applying stringent pollution level norms for vehicles
$VI.$ Switch over of public transport from diesel/petrol to $CNG$
Which of the statements given above are correct?

Minamata disease is a pollution-related disease that results from:

The addition of elements like nitrogen and phosphorus to a lake through streams leads to: