Which of the following are not  the cause of pollution?

i) Automobile exhaust
ii) Decreasing use of pesticides
iii) Waste chemical products from factories
iv) Radioactive substances

ii only.

The following are the causes of pollution :

i) Automobile exhaust
ii) Increasing use of pesticides
iii) Waste chemical products from factories
iv) Rise in atmospheric CO₂
v) Radioactive substances