For the JEE Main 2025–26 academic year, the syllabus has been rationalised in line with NCERT textbook changes. So yes, certain topics have been officially deleted and won't be asked in the exam.
In Physics, topics like communication systems, some detailed portions of thermodynamics (like the Carnot engine), and advanced concepts in waves, Doppler effect, and resonance have been removed. A few parts of kinematics involving vector products have also been taken out.
In Chemistry, chapters like surface chemistry, environmental chemistry, polymers, chemistry in everyday life, hydrogen, s-block elements, and metallurgy (extraction of metals) have been deleted. Some atomic structure and gas laws sections were trimmed too.
In Mathematics, topics such as mathematical reasoning, statistics, some parts of vector algebra and 3D geometry, principle of mathematical induction, and certain portions of the binomial theorem have been dropped.
If you're preparing for JEE, it's a smart move to stick to the updated NCERT textbooks and official NTA syllabus.