In the province of UP, India there was a large section of Muslims who were known as Malkana Rajput. Hindu influence in their customs & beliefs was widespread to the extent that they worshiped idols despite the fact that they were Muslims. During 1922-23 the militant wing of the Hindu Arya Samaj devised a plan to reconvert these people to Hinduism. Consequently scores of Malkana Muslims reverted to Hinduism. As soon as Hazrat Khalifat al-Masih the Second came to know of this apostasy movement he immediately launched a counter campaign.
Thousands of Ahmadis offered themselves to do the missionary work for a period of three months. They traveled to Uttar Pradesh at their own expense and started the missionary work with great zeal. Huzoor(ra) set up a network of Ahmadiyya missionaries whereby new batches of missionaries were dispatched replacing the outgoing ones. These missionaries of Islam rigorously worked there day and night. The movement of apostasy petered out in due course. Thousands of Muslims were saved from being converted to Hinduism. Of those who did convert, subsequently decided to join the fold of Islam.
The movement spearheaded by Huzoor was so successful that Muslims of India openly acknowledged the services rendered by Ahmadis to the cause of Islam.