Employer demoted me after I reported harassment, is this legal?

I work in a tech company in Hyderabad. Two weeks ago, I reported a senior colleague for harassment to HR. Instead of helping, HR demoted me from my position citing performance issues, which weren't mentioned before. This feels like retaliation for my complaint. I'm feeling helpless and don't know how to handle this. Is my employer allowed to do this legally? What are my rights and how should I approach this situation?