Purchasing Power Parity: How Google, Microsoft etc give 60-90 lakhs package to freshers from India for US location and give only 15-20 lakhs Max package for India location for the same position? Whats the reality?

It has nothing to do with a particular company in question or discrimination. It is all about economics  : http://en.wikipedia.org/wiki/Purchasing_power_parity and exchange rate play the havoc here. A MCDonalds burger which costs Rs. 60 in India will cost $8 in USA. If you convert in terms of rupees, it comes to Rs. 480/-. You see, Rs. 500/- vs Rs. 60/- for the same item. Similarly, a decent flat in Bangalore is available on rent at Rs. 30,000/- per month. A similar flat in California will cost you  Rs. 60,000. A taxi ride in any Indian city doesn't cost more than Rs. 1000/- , while in the USA it costs more than Rs. 6,000/- The outcome of this disparity is reflected in everyone's wages, right from a taxi driver to president. Lets say, a taxi driver in the USA earns ~$ 50,000 yearly (a little exaggerated ?) which converts to  Rs. 30 lakhs. To earn this income in India, you have to be in top notch position in an MNC. With a decent life, you can still save Rs. 20 lakhs. But the taxi driver there in the USA will not be able to save, say more than Rs. 3-4 lakhs, that too living a frugal life.