The alleged coal block allocation scam came under judicial scrutiny on September 14 when the apex court, on a PIL by advocate M L Sharma, had directed the Centre to explain if the guidelines on allotting natural resources to private companies were being strictly followed.

Expanding the ambit of judicial scrutiny of the alleged irregularities, the bench today also issued notice to the CBI on a plea for appointment of a SIT and the cancellation of allocation of 194 coal blocks to various companies.

In the fresh PIL filed by members of civil society and NGO Common Cause, the petitioners sought quashing of the entire allocation of coal blocks to private companies, made by the Centre from 1993 onwards.

"The involvement of senior ministers, public servants, different departments of Centre and state governments concerned in the alleged corruption and bribery by beneficiary companies need to be investigated.

"Considering the magnitude of investigation and possibility of involvement of high public offices, including the PMO, and the fact that CBI functions under the same very government it is supposed to investigate, a court-monitored investigation by an SIT is required to ensure proper investigation in the matter," the petition said.

The petitioners alleged that allotment of coal blocks was non-transparent and conducted in an unfair manner in violation of various rules and procedures.

"That investigation of CBI at the instance of CVC is partial and does not cover the full magnitude of the coal scam. The alleged conspiracy in blocking the policy of competitive bidding and the manner in which the screening committee functioned need to be investigated thoroughly, which involves senior ministers including the highest executive office of the country," the petition said.