Do you have any other Indian relatives or older friends who could talk to your parents? They need to realize first it’s much more lucrative to be a good lawyer or a government official than a bad engineer, and second, that it’s not enough to study hard, you need natural abilities to be a good engineer. Your parents can’t really mean minimal wage jobs are their only acceptable alternative to engineering. Presented with this choice as inevitable, my guess is they’ll warm up to a change of major. Then you’ll need to talk to your academic advisor and find a way to do this.