Q: Guruji, How does the Karma of our parents and ancestors affect us? Are we also punished because of their bad karmas?

Sri Sri Ravi Shankar: Listen, if your ancestor has left you a house, is it not a boon for you now? They have earned a lot of money, toiled and built a home and they left it to you. You are enjoying their karma, is it not?! And if they are gone with a big debt in the bank, and if you have to pay that back then that is your karma too. So naturally it affects you.
Not just parents but your company also affects you. If you keep sitting with very depressed people, you also feel down and depressed as well. If you are in the company of joyful and spiritual people your karma improves. You have no escape from bad or good karma in the world. We have to carry on with this, because there are times when we have to interact with people who are sick. You cannot say I don't want to be near sick people. If everybody says that then what will happen to all the hospitals and the patients? So in the world we need to be with everyone, and that is why being in knowledge and seva will help shield you. These are called Kawach.
Chanting Om Namah Shivaya is like an armor around you, it is like a Kawach. It protects you from all the unwanted karma, and other not so good effects are shielded. But you don't have to chant Om Namah Shivaya 24 hours a day. If you do that, your brain will become so dull. Just for a few minutes every day, like brushing your teeth.
Just like dental hygiene, you need mental hygiene as well. A few minutes of chanting, a few minutes of meditation, all these will help.