Dear Dhanush, you need to change your Category. The 27% reservation foor Backward Castes is for those who fall under the Non creamy layer. If  you do not have the income certificate, it will be assumed that you belong to Creamy Layer and then you do not get OBC benefits. So it is as much equal to General Category. https://jeemain.nic.in/WebInfo/Handler/FileHandler.ashx?i=File&ii=32&iii=Y states that Candidates who are not in OBC NCL list should select General as their Category.