The main reason behind price rise in real estate property in Chennai in the short period of time is the migration of people. When many people migrate into a city than out, the pressure of the demand causes real-estate prices to rise. Also there is every class of buyers like big landlords, industrialists, NRI's, traders, well advanced doctors and lawyers etc. who are ready to spent 60 lakhs to crores for their dream lands. After buying these lands, they have to spent additional amount of 40 - 50 lakhs on construction and renovation to build their dream houses.
There is a period of time among the housing permits and the finishing of building construction. Therefore, in the short-term, as people shift for jobs and schools, housing prices can move away from what's affordable for people in the long-term.
Rental prices are basically limited by people's income, but resale prices are not necessarily limited in the short-term, as long as people can finance their purchases.