Section 11D was held to operate prospectively because its penal...

Section 11D was held to operate prospectively because its penal character and plain language indicated application only to amounts collected after its introduction on 20-9-1991. The decisive factor was when the duty-like amounts were collected, not the date of the show-cause notice. The non obstante clause gave the provision overriding effect over inconsistent rules, but did not make it retrospective. Collections made before 20-9-1991 could not be recovered under the section, so the demand was unsustainable.