ICT Mumbai has 30% all india quota filled through jee mains scores. The greatest advantage is there is NO RESERVATION in this 30% quota..only merit!! As mentioned in question for chemical branch there are 30 seats available under this quota filled on the basis of jee mains score. All you have to do is visit the site regularly,apply for admission online, upload the required documents properly. After that ICT publishes a merit list of the applications received; thus you will get a rank in that list based on your score. Then the admission round is held in ICT itself..most of the top rankers in merit list take chemical; though some don't turn up for admission round and a few take other branches(top rankers). So the 30 seats for chemical, in my case were filled up to rank 40 approximately in ICT's merit list. This is the general procedure for admission through jee mains score. Now coming to marks in jee mains vs rank in ICT's merit list..well it differs on the basis of who all apply for admission and there can be no generalization as such. In my case my jee mains 2016 score was 192 and rank in ICT's merit list was 12-13.
Hope this helps.
Malhar Mankar, studied Chemical Engineering at Institute of Chemical Technology, Mumbai (2020)
Source: Quora Digest