Giving them benefit of doubt, the court said there was lack of evidence, especially regarding the identity of the accused.
It further referred the matter to Delhi State Legal Services Authority for rehabilitation of victims.
Around 19 PAC personnel were facing trial for allegedly killing 42 people in Meerut in Uttar Pradesh in May 1987. Three of them died during the trial.
The killings had allegedly occurred during riots in Meerut city after the victims were picked up from the Hashimpura Mohalla of the city by personnel of the 41st company of the PAC during a search operation.
The chargesheet in the case was filed before Chief Judicial Magistrate, Ghaziabad in 1996. The case was transferred to Delhi in September 2002 on the order of the Supreme Court following a petition by the families of the massacre victims and survivors.
A Delhi sessions court in July 2006 had framed charges of murder, attempt to murder, tampering with evidence and conspiracy against all the accused.