Can my landlord increase rent mid-lease in Bangalore?

My landlord in Bangalore just informed me that he wants to increase the rent by 20% starting next month. We signed a 2-year lease agreement just 6 months ago with a fixed rent amount. I am shocked and stressed as I budgeted based on the original rent. I need advice on whether he can legally do this and what my options are if I refuse to pay the increased amount.