The National Board of Revenue (NBR) issued an order requiring remittances of all types of taxes to be made through electronic means only. Hitherto, tax payments could be made through pay orders, treasury challan (a document or form, comparable to a cheque, serving for the crediting of funds from one account to another), A-Challan (automated system for the submission of various government fees) or e-payment. The order scraps pay orders and manual treasury challan as valid means for the remittance of taxes. Henceforth, remittances of all taxes must be made through either A-Challan or e-payment.
Source Orbitax