New Delhi, April 4 -- On a recent Friday night in Bengaluru, Green Theory, a cafe that serves plant-based food and drinks, turned into a retro-futuristic space for a silent music party. As neon lights shimmered and kitschy visuals reminiscent of 1970s movie posters played on transparent curtains, a crowd of around 100 headphones-clad youngsters moved to lo-fi disco music spun by DJ Joel Sakkari on the console. You may think this is a regular Friday night scene in Bengaluru, and it is, with one key difference: There is no alcohol in sight at this party. Instead, people drink zero-proof cocktails made by the in-house bar, Practically SoBar. The menu features drinks like Manisha is Complex made from non-alcoholic gin, clarified watermelon an...