Since it's inception, In Defense of Animals (IDA), has been actively involved with rescuing of abused animals, providing shelter, campaigning to secure legal recognition of animals, and promoting Animal Birth Control (ABC) program.
They have segregated volunteers into several groups. You can help them get new recruitments, helping in rescues and raise donations, create campaigns and content, and tend to the daily needs of the animals at their shelter. You can also opt to be a 'Guardian Angels' wherein you can sponsor a pet of your choice for INR 12,000 per year.