I need my birth certificate now for an urgent need. But I don't have that and also I know that it's not regist?

If it is not registered, then getting it from Kerala will be tricky. Normally the 10th class certificate works the best, Most probably you are not having it with you at present that's why the panic. Try an affidavit from a NOTARYwith a 'show cause', for this you'll need one of these, bank pass book, or D/L, or any E- card for which you had to fill a form mentioning your DOB some times even a used railway ticket/air ticket works very well to convince the Notary officer. In the mean time you can alway ask someone to FAX your papers from Kerala. Don't panic, if you have your bank's E mail ID your bank manager can immediately issue a nominal proof of your DOB which you can submit at the Notary. Don't worry such things can happen with any body.