Hello Jayashree,

There has been no notification about any changes by the higher authorities but any change will be mentioned on the official website so don't worry and continue with your preparations. 

The syllabus of AIIMS MBBS entrance exams includes the chapters given in NCERT textbook of physics, chemistry, and biology of class 11th and 12th. 

Nothing extra is asked other than that of these chapters. 

Have basic concepts about every unit and focus more on NCERT textbook. 

You will have a good probability of clearing your exam.

https://medicine.careers360.com/articles/aiims-mbbs-2019

You can use the above link for more information.

Good luck!