Hey dear, 

For being eligible for NEET. One should be a regular student for class 11 and 12, there should be no gap between these 2 classes and if you have taken a year drop after class 10th that won't effect much unless you were regular in your studies in 11 and 12

Dear Samar,

According, to the eligibility criteria you are eligible if you have studied English, Physics, Chemistry and Biology for two years as a regular student in a school.

A gap between Class 10 and Class 11 does not matter as long as you have studied Class 11 and Class 12 in continuous years with the necessary subjects.

Good Luck!!