Obc criteria as of 2019

I started preparing for central government exams recently, i am from chennai,tamilnadu.I am from obc community which i checked through obc list provided in national commision for backward class website .the OBC non-creamy layer criteria is the confusing and tiresome process if I start to find an answer to the question "am I belong to obc ncl". can someone please clarify which layer I belong to, and I also want the correct document that substantiates the answer, so that in future if any discomfort arises I can submit these as a proof in front of respective officials, and please explain how I can get the answer through RTI if there is an option available. below I mentioned the details 1.my father works as a driver in the state transport corporation 2.my mother works as a senior health nurse in the state health department(earlier assistant natal mother) 3.we do not have any agricultural land or any other business 4.both of my parent's salary together comes around ten lakhs 5.i am not sure which category they fall under state criteria of obc ncl ( class-1 or 2 or 3 or 4 ?)