Specified income exemption for development authority depends on non-commercial activity, unchanged functions, and prescribed return filing. Section 10(46) exemption is notified for specified income of the Baddi Barotiwala Nalagarh Development Authority, comprising government grants, revenue receipts under the Himachal Pradesh Town and Country Planning Act, 1977, and interest on bank deposits. The exemption applies for assessment years 2024-25 to 2026-27 and is conditional on the Authority not engaging in commercial activity, maintaining unchanged activities and income character, and filing its return under section 139(4C)(g). Non-compliance may attract penal action and withdrawal of the exemption.