Singh is under fire from supporters of social activist Anna Hazare for alleged irregularities in the allocation of coal blocks during his direct oversight of the nation’s coal ministry.

The group known as Team Anna has charged that Singh rejected advice to auction state-owned coal fields which resulted in massive financial losses between 2006 and 2009.

In March, a leaked government audit suggested state miner Coal India squandered more than $US200 billion by allocating coal blocks instead of allowing competitive bidding.

The report which the Times of India called “mind-boggling” ruffled reformers within the Indian coal industry, led to the opening of public coal block auctioning and has recently resulted in direct corruption accusations against the country’s chief of government.

Singh has since responded by promising that he would leave public life if “even an iota of truth” was verified in the allegations as pressure mounts for an independent investigation.

The government defended the allocation of coal assets in a statement yesterday from the Ministry of Coal.

“If the coal blocks were not made available between 2005 and 2010, it would have resulted in higher imports causing outflow of foreign exchange and would have had deleterious effect on large investments in crucial sectors like power and steel,” it said.

The ministry said allocation of coal blocks was intended to assist Coal India’s lone stewardship of the industry and accommodate the needs of the country’s expanding energy sector.

“[T]he allocation of coal blocks was never looked upon as a potential source for generating revenue for the central government,” it said.

Opposition party members and former Supreme Court justice Santosh Hegde have reportedly urged Singh to cooperate with an investigation although the jurist expressed reservations about Team Anna’s accusations.

“I myself am finding it very difficult to believe that there could be any charge or allegation of corruption against Manmohan Singh,” Hegde told New Delhi Television.

“I am finding it extremely difficult to believe, but at the same time, the things are happening in this country in such a way that at least let him clear himself of this allegation. I think some enquiry should be conducted.”

The scandal has so far targeted Singh’s reputation as an economist rather than his honesty or other personal leadership characteristics.

“I always saw the PM as a non-corrupt personality,” Hazare was quoted as saying by India’s Zee News.

“If there are corruption allegations labelled against him, he should come clean.”