Tiffin Collect, deliver, return: 200,000 tiffins daily5,000 Mumbai dabba-wallas take hot lunch from home to school/ office by train, cart or bicycle for ₹500 rupees (£5 / $7) a month.  Without computers or client phone numbers, they achieve Six Sigma competence level by scribbling alphanumeric codes on tiffins.  Every tiffin changes hands >5 times on…