Question

Up to what extent pesticides are harmful or harmless

Answer 1

if pesticides r used in a limit then they r not harmful. but if they r used excessively, then they can be harmful to the soil.

Answer 2

pesticides are very harmful because when they are washed away by the rains they get into the river bodies and leads to the algal bloom.This algae covers the water bodies from top and the oxygen supply into the water bodies gets cut off due to which the marine life gets affected.When these algae dies this leads to more shortage of oxygen because the microbes takes up more oxygen for decomposing them.
Pesticides are also harmful in many other ways