Building green is definitely important. But equally important is to know how green is a green building. Take the glitzy, glass-enveloped buildings popping up across the country. It does not matter if you are in the mild but wet and windy climate of Bengaluru or in the extreme hot and dry climate of Gurgaon, glass is the in-thing. I have always wondered how buildings extensively using glass could work in such varied climatic zones, where one needs ventilation. Then, I started reading that glass was green. Buildings liberally using glass were being certified green. How come?