The Tata World Nano will have a better finish, safety features such as airbags and will have a bigger engine. The Tata Nano Europa which is presently the center of attraction at the Geneva Motor Show has a 3-cylinder engine. The World Nano will have a similar engine with a sub-100 gram/km CO2 emission.
Whether or not the Tata World Nano will sail to the U.S is still speculative, but markets such as south America and southern Europe will sure love the Nano. We'll have to see how many more Mamatas politicians this little warrior has to fight before it finds homes in countries abroad.