Hello,

Yes, you can apply for AFCAT even if there is one year gap in education. But you need to fulfill the age criteria. The minimum age limit for flying branch is 20 years and the upper age limit is 24 years. For Commercial Pilot License holders issued by DGCA the upper age limit is 26 years. For ground duty technical and non technical the lower age limit is 20 years and the upper age limit is 26 years. You must also fulfil the education eligibility criteria for the post  you are applying. Here is the link where you can check the education requirement and the eligibility to join in Indian Airforce

https://afcat.cdac.in/AFCAT/CareerAsPerBranches.html#groundDutyTechDiv