Hi,
The objective of The All India Bar Examination (AIBE) is to examine an advocate's capability to practice the profession of law in India. The AIBE will assess skills at a basic level, and is intended to set a minimum benchmark for admission to the practice of law; it addresses a candidate’s analytical abilities and understanding basic knowledge of law. After passing the examination candidate will be awarded "Certificate of Practice" by the Bar Council of India.

According to the BCI rules, "RESOLVED that as the Bar Council of India is vested with the power of laying down conditions subject to which an advocate shall have the right to practice, these Rules, therefore, lay down such condition of an All India Bar Examination, the passing of which would entitle the advocate to a Certificate of Practice which would permit him/her to practice under Chapter IV of the Advocates Act, 1961.

No advocate enrolled under section 24 of the Advocates Act, 1961 shall be entitled to practice under Chapter IV of the Advocates Act, 1961, unless such advocate successfully passes the All India Bar Examination conducted by the Bar Council of India.

It is clarified that the Bar Examination shall be mandatory for all law students graduating from academic year 2009-2010 onwards and enrolled as advocates under Section 24 of the Advocates Act, 1961."

No Advocate can practice before being awarded "Certificate of Practice" from BCI. I hope it helps!