Why should the spraying of DDT as an insecticide on vegetable crops be banned ? Explain.

Spraying of DDT produces pollution of

Now-a-days use of DDT as insecticide is banned because

DDT is banned because:

One of the main objectives of biotechnology is to minimize the use of insecticides on cultivated crops. Explain with the help of a suitable example how insect resistant crops have been developed using techniques of biotechnology.