Tax exemption for pollution control board income conditioned on noncommerciality, unchanged activities, and specified return filing. Specified categories of income of the Andhra Pradesh Pollution Control Board are notified as exempt under clause (46) of section 10 of the Income tax Act, including consent fees, analysis and survey fees, central board reimbursements for monitoring programmes, biomedical authorization fees, cess reimbursements and appeal fees, government grants, RTI fees, non commercial sale of law books, interest on staff loans, miscellaneous receipts and interest on these incomes. The exemption is conditional on no commercial activity, unchanged nature of activities and incomes across years, and specified return filing compliance; retrospective application is stated as subject to a pending special leave petition.