I read this story long back in my Malayalam textbook, but I believe that it was translated from some other language (probably Russian?).
The rough plot - from what I can remember - is like this:
An angel visits the earth but is warned that she will lose her wings if she cries. She comes across a lot of sorrow on earth, but does not cry. But in the end, she comes across a mother who lost all her sons in war (guess that was it), and ends up crying.