The left sought to spoil the celebratory mood of the UPA's third anniversary on Tuesday, with a CPI-M member demanding a JPC probe into an alleged coal scam which has reportedly caused a loss of over Rs 1.8 lakh crore to the exchequer.

"Three years of the UPA government have seen scam after scam. Now we have yet another scam. CAG report (on coal scam) has not been placed in Parliament but estimates show that this scam is more than the 2G spectrum scam," CPI-M member Bansa Gopal Chowdhury said during zero hour in lok sabha.

Noting that coal mines were nationalised by then prime minister Indira Gandhi to the benefit of the country and its workers, he said, "Since 2004, coal blocks are being leased to private sector. Public sector coal India limited (CIL) is now being hijacked by private companies."

He said the CIL, a Maharatna company, has the financial strength to exploit the entire coal reserves in the country and there was no reason to allow private sector entry.

Chowdhury claimed that the private companies were taking over large chunks of land from farmers without paying any compensation to them. Of the 155 coal blocks given to the private sector, no work has begun in 124 of them, he claimed.

Alleging that national resources were being looted, the CPI(M) member demanded a thorough probe into the "scam" by a joint parliamentary committee.

The issue earlier led to adjournment of both houses of parliament during question hour as opposition created uproar over delay in tabling a CAG report on allocation of coal blocks.

Chowdhury had led a group of left members to the well vociferously demanding that the government table the report of the comptroller and auditor general on allocation of coal blocks.

The members, waving copies of a newspaper on the CAG report, raised slogans like '3 years of UPA, more than 30 scams', 'Down with the UPA government', 'Is this the way a democracy functions'.

The CAG report is reported to have blamed the government for extending "undue benefits" to private entities in connection with coal block allocation.