Exemption under section 35AC: approved charitable projects qualify for capped tax deduction under notified limits. Exemption under section 35AC approves specified charitable institutions and their named projects as eligible for deduction, prescribing for each the eligible activity (construction, equipment, running services), estimated project cost and the maximum cost amount allowable as a deduction, sometimes with an additional specified corpus fund component; the approval is time-limited to a defined three-year assessment window and issued on recommendation of the National Committee.