New Delhi, Sept. 17 -- From 15 October, Unified Payments Interface (UPI) merchant transactions move from a zero-fee structure to a modest, tiered one, a narrow change with wider implications for how India's payments system sustains itself. The standard fee is 0.4%, applied to person-to-merchant payments above Rs.2,000 and capped at Rs.300 beyond Rs.75,000. Railways, telecom, insurance, fuel, and a few other essential categories pay a flat Rs.5 instead, while capital market transactions carry a lower 0.02%, also capped at Rs.300. Consumers pay nothing, and transfers between individuals remain free as before. Small and micro merchants are already exempt. Vendors receiving up to Rs.1 lakh a month through UPI QR codes stay at zero fee, and th...