Can my employer in Bangalore legally deny me maternity benefits?

I've been working with this IT company in Bangalore for the past three years. I'm six months pregnant, and when I applied for maternity leave, my HR said I'm not eligible for benefits because I haven't completed four years. I thought after 80 days of work, I'm entitled to leave and benefits. Is this legal under Indian employment law? What steps can I take to ensure my rights are protected?