Should we loan half price of our car or pay full in cash?

My dad and I are buying a new car of worth 19.5Lakh. They say it is advisable to buy car with some loan so that you are not marked by income task department, even if you can pay in full. Is this true? Or just a rumour Edit: By cash I mean, online bank transfer. Not physical cash. I can't edit the title of post sorry.