My manager is saying me not to leave etc etc. Then he told me that he won't be able to provide me relieving letter unless I serve my entire 3 months of notice period. But as this is urgent for me I have requested him to manage this, I am ready to work overtime and provide knowledge transfer within a short period of time but he is not agreeing. Moreover I have another 5 months of bond(Although I dont have problem to pay the bond amount). What can be done here?
Your manager is not an authority to stop you from leaving the organisation if you follow the procedures as per the rules and the conditions mentioned in the employment offer letter.
You dont keep requesting or begging the manager, you can communicate your decision to resign the job, invoking the conditions of employment in respect of the notice period.
You should send this communication in writing to the top management either in person or by registered post with a copy endorsed to your manager, secure the acknowledgment.
Dont remain silent by sending the resignation by email because that will not invoke any response and you will be unnecessarily stranded and this may hamper your employment opportunity in the new company.