No water in borewell

Why has our borewell stopped pumping water?


We are residing in Saraswathi nagar, Adambakkam,Chennai. We have a bore well pump 90 feet below. It was drilled 16 years back. But now it has stopped pumping water. We doubt if ground water exists. Can the same bore be flushed out and tried again? Shall we drill a new Borewell?

Pl kindly suggest.