Income tax 50 year old demand notice

look into the time barring aspect of the notice and accordingly move upon.

Assessing officer has limited power to issue notice for various year, like:
143(2)-6 mnth from the end of the FY in which ROI has filed.
144- (notice for best judgment assessment) notice can be send a specifying in section 153(1).
148- (notice for income escape assessment) can be send up up to 4yr or 6yr or 16yr for 1 lakh or more then 1 lakh or assets out side india.
153- (notice in case of search) 16 yrs.

Sec 148 above time limits will not applicable if notice order has been passed by court, tribunal or CIT.

The notice received is of an outstanding tax demand and not a fresh demand... so the period of limitation will not be applicable

If demand of order already passed and if it was with in time limit for that period and you are not paid that, it quite natural you should have to pay with interest and penalty.

It is above 50 years old and no records are available neither with the department nor with the asessee. There is no proof of the demand being a genuine one.

What can the assessee demand from the department as the proof of demand?

Tell me 1st the section in which you get the notice.