Live in Chandigarh for a few years, and you notice something. Your doors take a harsh beating. Peak summer pushes past 40°C, the monsoon soaks everything from July to September, and by December the mornings turn cold and foggy. Wooden doors can't keep up with that back-and-forth. They swell, crack, and start sticking in the frame.  Metal doors rust and heat up like a pan. So a lot of...