Hi Rangaswamy R,
Kindly refer the definition of "existing law" given under clause (48) of section 2 of Central Goods and Services Tax Act, 2017, which reads as under:
"existing law” means any law, notification, order, rule or regulation relating to levy and collection of duty or tax on goods or services or both passed or made before the commencement of this Act by Parliament or any Authority or person having the power to make such law, notification, order, rule or regulation;"
Since, Central Sales Tax Act, 1956 was passed by Parliament, said enactment shall be covered under the term "existing law".
Now, coming to transitional provisions, section 142(8)(a) provides that any amount recoverable under existing law shall be recovered as an arrear of tax under this Act. The verbatim of the section is as under:
"(8) (a) where in pursuance of an assessment or adjudication proceedings instituted, whether before, on or after the appointed day, under the existing law, any amount of tax, interest, fine or penalty becomes recoverable from the person, the same shall, unless recovered under the existing law, be recovered as an arrear of tax under this Act and the amount so recovered shall not be admissible as input tax credit under this Act;"
Kindly note that procedure for recovery of taxes is provided under section 79 of the CGST Act, 2017. Now, before proceeding to the procedure of recovery, a registered person has all rights to pay off said liability as a liability under this Act i.e. CGST [this spirit has been taken from above quoted Circulars by other experts]. Therefore, arrears of CST Act can be paid from balance lying in electronic credit ledger. The challan can be prepared in Form DRC-03 showing liability under the head "CGST" which can be utilised from credit ledger as per rule 88A of CGST Rules, 2017.