The low-intensity bomb used in the blast here did not have shrapnels in it and all the injured were hit by pieces of wall that broke following the explosion, police sources said today.
They said the bomb kept near the steps leading to the Dashashwamedh Ghat was placed in such a way that the maximum impact was directed to the ground where the arti was being held on Wednesday evening.
Though the nature of explosives is yet to be ascertained, the sources said there were no burn or shrapnel injuries.
Meanwhile, of the 37 injured in the blasts, one is said to be in a critical condition.
Forensic experts are examining the blast scene to find clues about the exact nature of the explosives used.
An Improvised Explosive Device (IED) was recovered from a metal dustbin at the site of the blast.
Banned terror outfit Indian Mujahideen (IM) has claimed responsibility for the blast in e-mails sent to media houses and said it "attributed" the attack to the demolition of Babri Masjid in 1992.
The blast occurred at 6:20 PM when thousands of devotees and some foreign tourists had assembled at the ghat for the Ganga arti ritual.
The blast left a child dead and 37 others injured.