Every rejected COD parcel costs you forward shipping, return shipping and the working capital tied
RTO is decided at checkout, not in transit — the cheapest fix is preventing a bad order from being placed rather than chasing it after dispatch.
OTP verification removes the largest single category of RTO: orders placed with a number that was never reachable.
Partial prepayment converts a free option into a small commitment, and even a token amount changes behaviour sharply.
Blanket COD blocking costs more revenue than it saves; risk rules targeted by pincode, cart value and customer history are the workable version.
It varies enormously by category, price point and region, and any single benchmark figure should be treated sceptically.
The full guide has the formats, the deadlines and the worked examples.