The Reservation in fovour of Ex-servicemen, Person with Disability, Sportsmen, Minorities etc may be called Horizontal reservation.
Horizontal reservations cut across the vertical reservations – what is called interlocking reservations. The percentage of reservation allotted to Horizontal reservation categories should be adjusted against percentage of SC/ST/ OBC and General categories in vertical reservation.
Even after providing for these horizontal reservations, the percentage of reservations in SC /ST and OBC should remain the same. It should not exceed the limit prescribed for these categories.
All reservations are not of the same nature.
There are two types of reservations, which may, for the sake of convenience, be referred to as ‘vertical reservations’ and ‘horizontal reservations’.
The reservations in favour of Scheduled Castes, Scheduled Tribes and Other Backward Classes [(under Article 16(4)] may be called vertical reservations whereas reservations in favour of physically handicapped (under clause (1) of Article 16] can be referred to as horizontal reservations. Horizontal reservations cut across the vertical reservations – what is called interlocking reservations.
To be more precise, suppose 3% of the vacancies are reserved in favour of physically handicapped persons; this would be a reservation relatable to clause (1) of Article 16. The persons selected against the quota will be placed in that quota by making necessary adjustments; similarly, if he belongs to open competition (OC) category, he will be placed in that category by making necessary adjustments.
Even after providing for these horizontal reservations, the percentage of reservations in favour of backward class of citizens remains – and should remain – the same.”
Hope the above explanation clears your doubt about it.