Vikky, for Starters, there is no minimum aggregate criteria for JEE Mains. You should have completed your 12th with Physics, Chemistry and Mathematics. Now Chemistry can be replaced with any vocational subject. But the aggregate is considered when appearing for JEE Advanced which is the gateway for IITs, NITs and GFTIs. For Candidates belonging to General Category, it is 75% and for Reserved Category Candidates, it is 65%. 75% or 65% is calculated from the marks scored in Physics, Chemistry, Mathematics, Language and any other subject other than these 4 with the highest marks will be considered. So you cannot exclude Physics from the subjects. So retain Physics, Chemistry, Mathematics, English and the top scoring subject between CS and Drawing and then calculate the score.