Charges on Contract notes

#1
Hi, Friends. For last few months Im trading at some brokerage house. The brokerage house charges following intraday charges:

1. Brokerage..........0.1% per leg
2. Serv. Tax..........12.36% of brokerage
3. STT..................0.025% of turnover(approx)
4. Other Charges....0.02% per leg

I want to know what are these "Other Charges" and why are they charged?
I have already asked this question to their local office but they were unable to answer. Can somebody help me with this please?