Hi Chandrasekar,
CBSE has reduced 30% of syllabus of Class 9th, 10th, 11th and 12th, not of any other class. As you are asking for Class 6th, there are no changes done by CBSE in the syllabus. Nothing is reduced and nothing is added.
Refer here for more info - https://news.careers360.com/cbse-board-exams-2020-21-change-in-syllabus-compared-2019-20
Feel free to ask doubts in the Comment Section.
I hope this information helps you.
Good Luck!
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile