There are two main categories which need to be covered immediately if the government is aiming at giving a semblance of a good governance. Firstly, Below Poverty Line (BPL) families who are all having a voter card, supposedly a very authentic document and secondly financially better off strata of the society who have PAN, Passports, Public Sector Undertakings (PSU) and Autonomous body I cards, government service I cards and a voter card as well. With this kind of huge data bank already available in the country giving a biometric identity to all these groups should easily cover more than 95% of the population in a small time. The rest can be covered by making UID mandatory for property acquisition, vehicle registration, admission to schools and reaping benefits of government schemes.
The country will appreciate and will be grateful to the Indian polity if this exercise is completed on a war footing in about a year or two for the stakes are too high. After all the government's subsidy, social and welfare programs are worth more than Rs3,00,000/- crores annually and a leakage of about 50% as per latest study of the world bank is too large a figure not to merit war scale national mission attention. In fact a much higher figure of about 70% loss was mentioned by an erstwhile congress prime minister of the country.
Similarly keeping a tag on economic activity of the main generators and guzzlers of black money through e-governance and UID linking, a huge sum can be generated in the government kitty. The government by dilly dallying on not taking immediate effective steps in having a UID system in place is missing golden opportunity of propelling the GDP growth levels to mid teens.