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You can donate money etc. to the n.g.o.'s to which you are familiar, N.G.O.'S must be registered under socities registration act, 1860.
or you can donate to any charitable society well known to you.
you can also form your own n.g.o. by taking atleast 7 dedicated members.
for detailed knowledge you can study, handbook for N.G.O.'S by nabhi publications.