Can the validity of a subordinate legislation be challenged on the same grounds available against a plenary legislation?

Constitution of India — Art.14 — Art.19(1)(g) — Art.19(6) — Poisons Act, 1919 — Subordinate legislation — Proportionality — Constitution of India — Art.19(6) — Proportionality test — Held: A restriction on a fundamental right must pursue a legitimate aim, be suitable and necessary, and be balanced against the individual's right. This four-fold test governs whether a restriction under Article 19(6) is proportionate. (¶54, 55, 56, 57, 58) Constitution of India — Subordinate legislation — Grounds of challenge — Held further: The validity of a subordinate legislation can be challenged on the same grounds available against a plenary legislation. These include lack of legislative competence, being ultra vires the Constitution or the parent Act, and being manifestly arbitrary or unreasonable. (¶23, 24) Constitution of India — Art.19(1)(g) — Hardship not a ground alone — Held further: Hardship caused to a section of society is not by itself ground to strike down a legislation that is otherwise fair and reasonable. Such State action must nonetheless be reasonable and proportionate to withstand scrutiny. (¶39) Maharashtra Poisons Rules, 1972 — Rule 18A — Rule 18B — Application of the proportionality test — Held further: A rule mandating denaturants for methanol is not proportionate where less restrictive alternatives exist and the industries' burden is met only by a possible benefit. Rules 18A and 18B held violative of Articles 14 and 19(1)(g); petitions and appeal allowed. (¶56, 57, 58, 60, 68)