Section 80g of the Indian Income Tax Act provides a tax deduction for donations made to certain approved charitable funds and institutions. Donors can receive a 50% tax deduction for donations to organizations with 80g certification. Both individuals and companies are eligible for this deduction. Organizations must apply for and receive 12a and 80g certification from the Income Tax department to issue donors with tax exemption certificates. 80g certification is granted to nonprofit organizations for social welfare activities and is valid for 1-3 years, while 12a registration has lifetime validity. Donations qualify for full or 50% tax deductions depending on the organization and if they are below or above certain qualifying limits.