Hello Dhanavendan,

The official cut-off list for 2019 has not been released by the NITs yet. The approximate cut-offs can be predicted based on previous years' cut-offs.

So I'm sorry to say but it is extremely difficult, almost impossible, for you to get into CSE or ECE in NIT with 30000 rank because in 2018 the closing rank for CSE was 9651 and that for ECE was 13,458. 

However, you have chances of getting admission in the Biotechnology, Industrial and Production Engineering, Textile Technology and maybe even Chemical Engineering branch.

Do not lose hope, there are many other colleges that may offer you admission in the branches that you like.

Hope this helps.