Why was the twenty-second of every month important to Gandhi?

Gandhi's suffering for the unfair blame for the violence was only exacerbated when one of his jailed associates, Mahadev Desai, died of a heart attack beside him in jail. On February 22nd, his dear wife, Kasturbai, also died in prison, her head on his lap. From that time until his death, he said prayers on the 22nd of every month to honor her.