They actually cut the syllabus for students below class X. It's not a ban or anything. And it's only NCERT's (central board of education) syllabus. Each state has its own education board and syllabus. The headline is not honest.
why have an educationally insufficient NCERT curriculum?
This insufficiency with weird omission for evolution and periodic table seems to be due to covid after effects or general incompetence rather than malice.
I studied in 3 different boards at different points of schooling and the rule of thumb was state board, NCERT/CBSE and ICSE in increasing order of “rigor”. The last two years of high school are spent in preparing for competitive entrance exams anyways, whose syllabus usually is a superset of the school syllabus in your chosen field (engineering, medicine, sciences etc.)