Though donations to charitable institutions is a noble cause, there is an upper limit on how much amount we donate can be used for tax exemptions. The general rule is "50% of the amount donated subject to a maximum of 10% of the Total Taxable Income of the Individual can be donated and exempted under Section 80G of the Indian Income Tax act of 1961". A point to note is that, any donations done beyond the allowed limit is not considered for tax purposes. However, there are some donations, where this limit of 50% of the donation does not apply. So, such donations can be exempt from your Tax Liability to the full amount.