hello,

Since you have completed your diploma in mechanical engineering you are eligible to apply in 2nd year through lateral entry. For that you have to give the entrance exam of your respective state or you can also give entrance for jee mains/ advance but if you appear in jee mains/advance you will have to start your engineering career from 1st year because there is no provision for special entry and thus, students have to appear in the jee advanced examination which is the only way to get into IITs for undergraduate course in engineering

hope this will help you

all the best!!