Electronic Cash Ledger rules govern challan-based payments, CIN crediting and ledger treatment for refunds and deductions. The Electronic Cash Ledger on the Common Portal records deposits and debits for tax and related amounts; payments require a Portal challan and may be made by authorized banking channels or OTC subject to limits and exceptions, with commission borne by the payer. NeFT/RTGS mandate forms accompany challans and banks generate a Challan Identification Number (CIN) on successful credit; absence of a CIN after debit permits electronic representation. Receipt of CIN effects credit to the electronic cash ledger and Portal receipt issuance.