Two companies, Forum Projects and PS Group, have taken the lead by adopting green building norms that set benchmarks in use of environment friendly material and energy saving systems. Forum Projects set up Technopolis, the first green building in Kolkata. PS Group is set to better the effort with the country's tallest green building.

"The need for green buildings is as much to mitigate global warming as it is to ensure a healthy environment. IT companies are demanding a green environment to avoid sick building syndrome," PS Group director Pradeep Chopra said.

Though green buildings require 20% additional capital investment, Chopra and Forum Projects managing director Rahul Saraf reason it makes perfect sense as the amount can be recovered in two-three years through savings in electricity and water.

Developers of several housing projects are also turning to environment as they see commercial sense in it. "A green environment is now a project USP. With KMC allowing vertical growth, developers want to showcase the greenery in the complex," South City Projects director Sushil Mohta said.

At the South City complex, the developers plan to plant several thousand trees and even carve out a waterbody. While a landscape architect is preparing the outdoor layout, a botanist has been engaged to transplant full-grown trees once the project is completed.

"If there is a lake adjoining the project site or an open expanse of green, it becomes a USP and can easily command a premium," acknowledged Silver Spring promoter Peeyush Bhagat.

Then there are the likes of Mangalik Cooperative Housing Society where residents have taken the initiative and turned the complex into a veritable botanical garden. "We take immense pride in what we have created. It has not only improved the environment, but has also gone a long way in sensitising the youth," said M K Chakraborty, secretary of the housing society.