Delhi Traffic Police — asked for money, when not paid, challan without valid reason

Address:

New Delhi, Delhi

I was stopped by delhi traffic police cop today morning for over speeding. My car speed was 64kmph against 50kmph. I paid challan for rs 400 for this. Along with this the cop ask for rs 500 more. When i refused to pay. He asked for my driving licence. I showed original valid dl, even after this he challan me for ₹500 more and mentioned reason that driver did not produce valid driving licence.
Same on delhi traffic police for this.