Landlord entered my flat without permission when I was not home, is this legal?

I rent a flat in Pune and recently found out that my landlord entered my flat when I was not there. He didn't inform me beforehand nor did I give him permission to enter. I feel this is a breach of my privacy. I confronted him and he said he was just checking the water supply, but I feel uneasy now. What are my rights as a tenant? Can I take legal action against him for this invasion of privacy?