In the JEE main NTA scores there are four scores given one is the percentile score in each subjects that is percentile score in physics, percentile score in chemistry, percentile score in mathematics and there is a total percentile score.

now the percentile score indicates the number of students which are behind you that is the percentage of students which are behind you so if you get 50% telesco it means the 50% of the total appeared students are behind you in the similar way it is calculated for three different subjects and commutative percentile score.