Before revision:  As discussed in S\"onmez and Yenmez (2019a), the lack of a well-defined procedure to implement horizontal reservations results in extensive confusion. Indirect mechanisms currently used in practice do not  allow reserve category applicants to fully express their preferences.
After revision:  As discussed in S\"onmez and Yenmez (2019a), the lack of a well-defined procedure to implement horizontal reservations jointly with vertical reservation and OBC de-reservations. Sequential processes currently in use for OBC de-reservations and meritorious reserve candidates lead to severe shortcomings. Most importantly, indirect mechanisms currently used in practice do not allow reserve category applicants to fully express their preferences.