(b)required to file a return in respect of a scientific research association, news agency, association or institution, fund or trust or university or other educational institution or any hospital or other medical institution or trade union referred to in sub-section (4C) of section 139, may make an application to the Assessing Officer for the grant of a certificate under sub-section (1) of section 197 authorizing him to receive incomes without deduction of tax at source.