NRI paid 30 lacs as advance for flat in FY 19-20 AY20-21 bal.30lacs in Fy 21-22. return for 20-21AY

assesses does not have any income in INDIA

NRI paid 30 lacs during FY 19-20 for purchase of lfat.

balance about 25-30 lacs will be paid in during 21-22 FY

My doubt is while registration  value of the flat exceeds 30 lacs, th same may be reported to the Dept.

On receiving such report, if the dept. asks for not filing the return OR source etc......

...what answer should I give.

Any action to be taken now....Please advise.