Firstly, having an ST rank of 593 means you're in the top 600 among ST candidates, but there’s more to how CLAT admission works. The total number of seats for ST category across all NLUs is limited, often just around 300–400. And even though your category rank is 593, it’s possible that other candidates ahead of you filled up most of the seats in earlier rounds.

Also, your All India Rank (AIR) of 34,347 plays a role because some NLUs consider both AIR and category rank during seat allocation. Most ST category cutoffs in popular NLUs tend to fall around AIR 12,000–20,000, depending on how competitive that year is and how many applicants fill seats in the early rounds. So, if your AIR is outside that range, it's quite likely you were just beyond the last cutoff in round-wise seat distribution.

The best move now is to look out for mop-up or spot rounds, where unfilled or withdrawn seats are re-offered. Also, many private universities like UPES, Nirma, or Bennett accept CLAT scores and reserve seats for ST category students.

All the best!