The MHRD did announce that NEET 2021 will be conducted on a reduced and revised syllabus owing to the decreased academic year 2020 due to Corona Pandemic. The department has invited suggestions from the parents. At this point in time, the syllabus hasn't been decided yet. So it is not still unknown what are the topics that might be included and what topics might be omitted. But yes the syllabus will be reduced. So if you are preparing for NEET 2021, stick to NCERT books until the official syllabus has been officially released. So if you are already studying for 12 hours, we would suggest you to just go with the flow atleast until the new NEET syllabus is released. For now try to complete the syllabus taught in the school the same day. Only on the weekends, attempt atleast one mock test. You do not want to spend time on topics which might not be included in the NEET 2021 syllabus. So sticking to what you are being taught in the classes and practising mock test every week, will keep you updated and save your time.