Actually what happened..the buildings in these areas have less height because builders have not utilized the permissible floor space index which is the ratio of land area to built-up area. And thus during redevelopment, government will make sure to use the permissible limit and shall build more apartment units.
Yes ..around 17 housing board residential enclave will be redeveloped in various parts of Chennai city. The areas chosen are Peters Colony and Lloyds Colony in Royapettah and Todhunter Nagar in Saidapet...they were in very bad condition.The government is planning to construct multi-storeyed apartments at these locations.