Hello
PRATIK PAL , In 2019 almost 66,958 candidates have appeared in IIT JAM 2019. This year, almost more than 3000 candidates are increased for physics and chemistry from last year. The total seat 2223 for IITs and 1412 for NITs are available in IIT JAM 2019. So it is approximately same or increased by 3000.

Hope it will be helpful for you :)