Very sorry to hear that, I am also an NRI and it happened to me also, I paid us$ 100 as a bribe to Mumbai Immigration to let me take my Luggage which had some electronics item or they told me that they will confiscate the bag, one of the Senior office there ordered to Junior officer (Hawaldar Pandu) to take me to washroom and give him 100$ over there, I paid 100$ to release my luggage and the funny part is that Pandu Hawaldar was also asking me to give him some more money for himself, I just shouted on him and left, so always be ready with Minimum us$ 50 note or Us$ 100 note maximum if u want to pass immigration without any hesitation. THIS IS INDIA MY GROWING NATION WHERE OFFICIALS ARE CHEATER.
So next time be ready if you are landing at GREAT CITY------------------MUMBAI