Rental agreement dispute

Hi Sir, I have been staying in rented house for 11 months now with a rent of Rs.17,850/month. The rental agreement is from 1-06-2014 and for period of 11 months with an advance 2Lakhs given. The notice period is not mentioned in the rental agreement made. Since we will be completing 11 months as per the contract on April 30th 2015 and didn't want to renew the contract we informed the landlord upfront.(on MAR 28 we informed about vacating the house by APR end) Now the owner is arguing that 2 months notice was required and is a norm in Bangalore. He will be deducting one month extra rent + painting charges. The argument he is giving is that he is not able to get a new tenant in this short notice and he is incurring loss as he has to pay brokerage charges again. What is the nominal notice period which needs to be served if notice period is not mentioned in the agreement. Am I really obliged to pay one month extra rent as we are not serving 2 months notice period ? How can I deal this situation legally ? I am planning to vacate the house by April 30th 2015. Please advice.