STATE OF TAMIL NADU vs M. KRISHNAPPAN .

The Supreme Court examined the constitutionality of Section 4(1-A)(a) of the Tamil Nadu Motor Vehicles Taxation Act, 1974, which mandates a one-time lifetime tax for new vehicles based on a 'weight-cum-value' index. The Court held that the tax is not compensatory as it does not correlate with road maintenance costs, thus violating Article 14 of the Constitution by being arbitrary and discriminatory. The judgment of the Madras High Court was upheld, affirming that the differentiation between old and new vehicles lacked a rational basis.