Can landlord increase rent mid-term without notice in Chennai?

I've been renting an apartment in Chennai for over a year, and suddenly my landlord sent an email saying my rent will increase by ₹5,000 starting next month. My lease agreement is supposed to be for two years with no mention of mid-term increases. I feel this is unfair and I can't afford the sudden hike. I haven't agreed to this increase, but I'm worried about eviction threats I've heard from others. Do I have any legal grounds to challenge this?