Dear student,
Different colleges hae different criterias for accepting caste certificates. At the time of admission if you have a valid caste certificate and your income certificate shows your income less than 8 lakhs per annum then you will be definitely considered as obc ncl, but uf you fail to produce it then you will be shifted to general category. Some colleges also ask for income certificate every year if the students enjoy the facility of tfw. If such is the case with you then in the subsequent years if you fail to produce the required certificates then you will be shifted to general.