There was a science fiction series on UK television some time in the early 70s. I was too young to understand it properly, but I've wondered about it ever since.
In the story people were suddenly filled with an irrational hatred of technology. I remember a scene of a mob beating a car with sticks. A boy and a girl eventually find the source of this, which is a lump of rock in a cave. At some point the girl also spends time with a group of sikhs who don't seem to understand what is happening: the girl sees them trying to start a car and has to explain that using technology will get you into trouble. They see that she has some insight into what is going on, and take her in as an adviser.
Does this ring any bells with anyone?