What is a CIN and what is its relevance?

CIN stands for Challan Identification Number. It
is a 17 digit number that is 14-digit CPIN plus 3-digit
Bank Code. CIN is generated by the authorized banks/
Reserve Bank of India (RBI) when payment is actually
received by such authorized banks or RBI and credited
in the relevant government account held with them. It
is an indication that the payment has been realized and
credited to the appropriate government account. CIN
is communicated by the authorized bank to taxpayer as
well as to GSTN.