Lots of reasons, sabotage, low fluid, defective parts, failed or broken parts, etc.
This grossly unsafe. If you have just the booster fail the brakes will still work but not well. If the brakes fail completely you could crash and die.
It would be against the law for a motor manufacturer to fit a light which could cause the brakes to fail.
They can if the brakes are out of adjustment or have a mechanical problem.
I would advise bringing your car to a mechanic as quickly as possible. Your brakes could fail. This puts you at a high risk for injury or even death.
Your pads or discs are worn. The brakes will fail soon if not replaced.
no
excessive heat caused by using them too much brakes out of adjustment.
Answering "How do you fix a 1995 Chevrolet Lumina emission test fail NO x ppm reading fail?"
Highly doubtful because the front and rear brakes are independent of each other.
Dry them.
yes, its really risky because driving with bad brakes can probably cause a hydraulic failiure your brakes can fail and you dont want to know what happens so get your brakes checked
My guess would be the master cylinder failed.