Whether a circular contrary to the provisions of law is valid and enforceable in the eyes of law?

Glaxo SmithKline Pharmaceuticals Limited (Formerly known as SmithKline Beecham Pharmaceuticals (India) Limited) Versus Union of India & Others - 2014 (3) TMI 113 - SUPREME COURT

It is well settled that if the departmental circular provides an interpretation which runs contrary to the provisions of law, such interpretation cannot bind the Court. 1979 circular falls in such category.