What does the given image represent?

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?

Eutrophication can be observed in

Which among the following is likely to have the highest levels of $D.D.T.$ depositions in its body?

The method of measuring Biochemical Oxygen Demand $(BOD)$ is used for which of the following?

Which of the following animals remained free from Minamata disease in Minamata Bay,Japan?