Paying bribe is mandatory

I had purchased an apartment in Bangalore C V ********** Nagar area in 2008, I was asked by my builder to pay up Rs11,200 at the registration office, if the house that I purchased requires registration hassle free.
I was told that its a MANDATORY bribe asked at the registration office and I handed it over at the office.Also every owner of the apartment did pay the same bribe amount at the registration office.
My builder told me not argue there else your work will never get done and they (officials) would put you into serious trouble.
So just pay and relax........................!!!!