From what I see it is not easy to evade tax for a long time since we need to show our pan card for any expenditure above a certain limit...so it goes on record , tracking may be slow but eventually they will catch up with those who are evading tax and have undisclosed income.
Tax evasion cannot be completely stopped. Tax tax authorities can make demand only within one year in normal cases and five years when suppression of facts, fraud etc is involved. Many evasions are not detected. secondly, if you make assets with the tax evaded money, you may be caught. If whole money is gifted or spent on consumable items, evasion cannot be caught.
G. K. Ajmani Tax consultant http://gkajmani-mystraythoughts.blogspot.com/
