Sorry, but if you were already offered the next job, does the next employer really care about a severance certificate? Why is a severance certificate important in India?
I'm not sure it really is - but it could be. I think it depends on the hidebound bureaucracy of the company you're applying to. It's been a while since I've worked in India (close to 20 years now). So things have most likely changed massively. When I was there I've known of folks who just quit and folks who gave a decent notice. Those that stayed the notice period got a severance certificate. Those that just quit didn't get one. I don't believe it impacted careers much. That time the notice period was 1 month, not ideal like the US 15-day notice but not too bad either (1 month was the pay period). When I left I negotiated the notice period down to 3 weeks. 2 to 3 months notice is oppressive.