About assesse under income tax act...?

[7] "assessee" means a person by whom any tax or any other sum of money is payable under this Act, and includes—

[a] every person in respect of whom any proceeding under this Act has been taken for the assessment of his income or assessment of fringe benefits or of the income of any other person in respect of which he is assessable, or of the loss sustained by him or by such other person, or of the amount of refund due to him or to such other person ;

[b] every person who is deemed to be an assessee under any provision of this Act ;

[c] every person who is deemed to be an assessee in default under any provision of this Act ;



this is the definition pf assesse as per income tax act. in that under clause a, what does it mean by has been taken.....

does it mean some proceedings under this Act were done in past or is going to be in future or proceedings were opened and still continues......what exactly is that.....