Test of valid classification :
Since a distinction is to be made for the purpose of enacting a legislation, it must pass the classical test enunciated by the Supreme Court in State of West Bengal v. Anwar Ali Sarkar, AIR 1952 SC 75. Permissible classification must satisfy two conditions, namely; (i) it must be founded on an intelligible differentia which distinguishes persons or things that are grouped together from others left out of the group; and (ii) the differentia must have a rational nexus with the object sought to be achieved by the statute in question.
After considering leading cases on equal protection clause enshrined in Article 14 of the constitution, the five- Judge Bench of the Supreme Court in Confederation of Ex-Servicemen Assns. v. Union of India, (2006) 8 SCC 399 stated: “In our judgement, therefore, it is clear that every classification to be legal, valid and permissible, must fulfill the twin test; namely :
(i) the classification must be founded on an intelligible differentia which must distinguish persons or things that are grouped together from others leaving out or left out; and
(ii) Such a differentia must have rational nexus to the object sought to be achieved by the statute or legislation in question”.
The classification may be founded on different basis, such as, geographical, or according to objects or occupation or the like. What is necessary is that there must be a nexus between the basis of classification and the object of the Act under consideration. A legal and valid classification may be based on educational qualifications (State of Bihar v. Bihar State ‘Plus-2’ lecturers Associations and Others, (2008) 7 SCC 238)
A law based on a permissible classification fulfills the guarantee of the equal protection of the laws and is valid. On the other hand if it is based on an impermissible classification it violates that guarantee and is void. Reiterating the test of reasonable classification, the Supreme Court in Dharam Dutt v. Union of India, (2004) 1 SCC 712 held that laying down of intelligible differentia does not, however mean that the legislative classification should be scientifically perfect or logically complete.