The report, which was submitted to the government last year, has highlighted the alleged nexus between land grabbers, Resident Welfare Associations and concerned authorities as certain non-existent colonies were also issued the PRCs in "violation" of laid down norms.
The report was filed by a committee headed by then Divisional Commissioner Vijay Dev.
It had recommended criminal proceedings against those involved in the irregularities and said a thorough probe must be conducted into the entire exercise of issuance of the PRCs in 2008.
But the probe committee said colonies, which did not comply with prescribed norms, were also issued provisional regularisation certificates.
The government had in September last year regularised 895 colonies out of over 1,200 colonies which were given provisional regularisation certificates.