Mr Pawar's swearing-in at the Raj Bhavan this morning was boycotted by the Bharatiya Janata Party (BJP) and the Shiv Sena in protest.
More trouble over his induction is expected during the upcoming winter session of the Maharashtra Assembly in Nagpur - Shiv Sena leader Sanjay Raut said today that a no-confidence motion would be moved against the Congress-NCP government.
The White Paper that cleared Mr Pawar of corruption charges in the irrigation scam has been prepared by the irrigation department held by his own party. Reason for the BJP to demand that Mr Pawar should face the special investigation team (SIT) probing the scam.
But the NCP veteran hit back today, saying: "It is wrong to say that I influenced the probe and that the White Paper was issued to benefit me. A White Paper is prepared after going into all aspects of a matter," Mr Pawar said.
"Anyone can file a PIL against anyone. If you say that unless the decision on a PIL comes out, the person should stay out of power, then no minister, no chief minister and even the Prime Minister will be able to hold any position and work."
Mr Pawar - the nephew of NCP chief and Union Agriculture Minister Sharad Pawar - was forced to quit as deputy chief minister on September 25 over allegations of irregularities as Maharashtra's irrigation minister between 1999 and 2009.
He wields enormous political clout in Maharashtra and his resignation had plunged the Congress-NCP government into a crisis with all other 19 ministers of the NCP offering to quit.
The resignation came in the wake of Chief Minister Prithviraj Chavan promising a White Paper on the alleged irrigation scam. Ties between the Congress and NCP, already strained, plunged to a new low.
The white paper on irrigation was presented on November 29 by Irrigation Minister Sunil Tatkare of the NCP. It claimed a 28 per cent increase in the state's irrigation potential in the last 10 years - Mr Pawar held the portfolio for most of this period.
The BJP's Eknath Khadse, Leader of the Opposition in the Legislative Assembly, has alleged Mr Pawar was brought back into the Cabinet under the NCP's pressure. "If he (Pawar) has guts, he should be ready for an SIT probe. If proved innocent, he can re-join the cabinet with respect," Mr Khadse said.
The Shiv Sena's leader in the Legislative Assembly, Subhash Desai, dismissed the clean chit to Mr Pawar. "He is still not in the clear. They (government) are fooling the people. It's an eyewash," he said.
But the NCP is cheering Mr Pawar's return. Party leader Sachin Ahir said: "We were wondering if we would remain headless or what? Good that Ajit dada has come back."
(With inputs from agencies)