Judge P C Rawal dismissed the prosecution's plea, citing the existing criminal law which allows panch witnesses to identify the accused only at an identification parade.
The state's contention was that panch witnesses would find it difficult to identify the accused at an identification parade after a lapse of many years because the accused had put on weight and grown beards while lodged inside Sabarmati central jail here.
Special public prosecutor H M Dhruv said the authorities cannot ask the accused to shave the beards as it could hurt their religious sentiments.
Twenty one blasts had rocked the city on July 26, 2008, claiming 56 lives. More than 70 accused are in jail now.
Twenty four of these accused had tried to escape from Sabarmati jail by digging a 218-feet-long tunnel in 2012 but the tunnel was found out before they could flee. The case related to this bid is being tried before the same court simultaneously.