Mr Yadav, however, noted that the notice was also a political vendatta against the Aam Aadmi Party (AAP).
"Of course its vendetta. But a party that took on the entire political system should have known better.
IT notice on solid grounds: AAP kept double accounts, concealed info from public and dodged tax authorities. Exposes AAP hypocrisy on financial probity and transparency," Mr Yadav tweeted.
The Income Tax Department has charged the Aam Aadmi Party (AAP) with taking "hawala entries" worth Rs 2 crore from a Delhi-based operative and revoked the tax exemption given to it for being a political party, for the assessment year 201516.
The taxman, according to the penalty notice, has alleged that the Kejriwal-led party in power in Delhi "incorrectly disclosed the hawala money as voluntary donations".
The department slapped these charges on AAP in its assessment order issued to the party last week and determined the total taxable income of AAP at Rs 68.44 crore with a corresponding income tax of Rs 30.67 crore for AY 2015-16.
Reacting to the notice Mr Kejriwal had termed it as the "height of political vendetta".
Mr Yadav and Prashant Bhushan, former AAP leaders, had questioned the funding of the AAP before they were ousted from the party in April 2015.