Departmental circulars and trade notices in central excise :

Under section 37B, which is titled “Instructions to Central Excise Officers”, the Central Board of Excise and Customs (CBEC or Board), which is constituted under the Central Boards of Revenue Act, 1963, shall issue instructions to officers who are bound to follow them. These instructions or orders can be for the purpose of ensuring uniformity in the classification of excisable goods or with respect to levy of duty of excise on goods. However, such orders cannot be passed to direct any officer to dispose of a case in a particular manner or interfere with the discretion of the Commissioner (Appeals).

The trade notice has a legitimate source of law and the same is binding on the departmental officers concerned. Authorities cannot take one stand in one State and another stand in another State. Trade notice issued by one Custom House must bind all customs authorities and, if it is erroneous, it should be withdrawn or amended.

[Steel Authority of India v. Collector of Customs Mumbai 2000 (115) ELT 42 (SC)]