I have got 469/650 in Maharashtra hsc board. Do I am in top 20 percentile?
Yes asper 2018 cutoff for top20 percentile in Maharashtra board, minimum marks was 354 for open category and hence you shall be eligible for NITs and IIITs and IITs under Jee Makn and Jee Advanced.
https://engineering.careers360.com/articles/top-20-percentile-of-class-12-boards-for-nits-iiits-and-cftis