Marking the biggest and first of its kind tie-up in the private sector, Real Estate major K Raheja Corp is working with former US president Bill Clinton-led Clinton Climate Initiative (CCI) to retrofit their buildings across the country to cut greenhouse gases. Work has started in Mumbai and Hyderabad, and according to the company, 50 lakh square feet of built space (in over 20-odd buildings) will be retrofitted. For the process, smarter glass varieties (which let in light, not heat) and better suited air-conditioning systems are used. Sewage treatment is also done to conserve and recycle water. While some government buildings have been retrofitted for cutting carbon emissions, the concept is still picking up in the private sector.