I was harrased by Pondicherry Police for Driving my friend's car alone and had to bribe them.

A.As per Section 197 of The Motor Vehicles Act, 1988 it makes it punishable act if someone drives a car belonging to other without his consent or authorization. But the point is that if the court is satisfied that the drives has a consent then he will not be punished.
To avoid all this kind of issues next time onwards carry a one page authorization letter from your friend.

Section 197 in The Motor Vehicles Act, 1988
197. Taking vehicle without authority.—
(1) Whoever takes and drives away any motor vehicle without having either the consent of the owner thereof or other lawful authority shall be punishable with imprisonment which may extend to three months, or with fine which may extend to five hundred rupees, or with both: Provided that no person shall be convicted under this section if the Court is satisfied that such person acted in the reasonable belief that he had lawful authority or in the reasonable belief that the owner would in the circumstances of the case have given his consent if he had been asked therefor.
(2) Whoever, unlawfully by force or threat of force or by any other form of intimidation, seizes or exercises control of a motor vehicle, shall be punishable with imprisonment which may extend to three months, or with fine which may extend to five hundred rupees, or with both.
(3) Whoever attempts to commit any of the acts referred to in sub-section (1) or sub-section (2) in relation to any motor vehicle, or abets the commission of any such act, shall also be deemed to have committed an offence under sub-section (1) or, as the case may be, sub-section (2).