The design, construction and maintenance of buildings has a tremendous impact on our environment and our natural resources. The buildings all together use the one-third of all the energy consumed in the country and two-thirds of all electricity. So the challenges is to build them smart, so that they use a minimum of nonrenewable energy, produce a minimum of pollution and costs a minimum of energy, while increasing the comfort, health and safety of the people who live and work in them. Here comes green buildings which alienates the isolation of sealed and vertically lit and ventilating buildings. With increasing degradation of environment because of increased energy consumption, environment conscious building design has become urgent. The benefits of green design to society in general and building owners and its users in particular are manifold. The construction of such buildings results in reduced destruction of natural habitats and bio-diversity, reduced air and water pollution, less water consumption, limited waste generation and increased user productivity. The cost differential between passive and conventional systems is hard to determine as passive elements are an integral part of the building architecture. However, it is believed that passive design could prove to be a cost effective solution and should not cost more than 15 to 20% of the total building cost. What is needed now is to educate society about energy conserving concepts and motivate architects and builders to design and construct such buildings. The sector is a promising one and is expected to develop further at a faster pace with the active cooperation of architects, engineers, builders and policy makers.