NEET - What is Open state and is Tamilnadu open state. Also please let me know when we have register for NEET admission

In India MBBS is taught in Government Medical Colleges, Private Medical Colleges and Deemed/central Universities. Admission to these Institutions is done through All India Counselling and State Counselling on the basis of NEET score. All the 15% of All India Quota Seats except for Jammu and Kashmir, 100% Seats at Deemed and Central Universities, IP Quota seats in ESIC Colleges, Seats at AFMC, AIIMS and JIPMER are filled by DGHS. The 85% State Quota and Private Colleges are filled by the respective State Authorities. And there are 3 Categories in Private Medical Colleges. Category A is the Government Quota Seats. And only candidates of the home State are eligible to apply for these seats. B Category seats are also called Management Quota Seats and they are filled through State Counselling and the remaining seats are filled through direct Admissions by contacting the College directly provided the Candidate has registered for the respective State Counselling and has not been able to secure a seat in the Counselling. Here the fees is usually nothing less than 40 lakhs. The last Category is NRI seats Category and you cannot apply for that. Now an Open State is a State which allows other State Candidates to participate in its State Counselling for admission to Management Quota seats. Himachal Pradesh, Haryana, West Bengal, Telangana and Tamil Nadu are few Open States. NEET is an entrance examination and you have to register either during your 12th or once you complete your 12th. NTA releases online registration forms usually in the month of December. You need to be 17 years atleast by December 31st of the year of admission to be eligible for NEET.